2014 Top 10 Prospects: Seattle Mariners

The Mariners organization features some exciting young arms with seven of the Top 10 players applying their trade on the mound. The front office has done an exceptional job of acquiring talent both through the annual amateur draft and the international free agent market. Every player in the Top 15 was originally signed by the club. Seattle will enter 2014 with one of the best systems in baseball.

To make the Mariners list even more enjoyable this year, I enlisted the aid of a writer who probably knows the the system better than anyone outside of the organization. Jason Churchill of Prospect Insider — who you might also know from ESPN — graciously agreed to provide his thoughts and opinions on each player in the Top 10. We both wrote our comments separately with no input from each other so you may find some contradictions but, for the most part, our reports share a lot of similarities.


#1 Taijuan Walker | 70/MLB (P)

20 15.0 7.20 2.40 38.1 % 3.60 2.25 3.80 0.2 0.5

The Year in Review: Walker didn’t turn 21 until midway through August but that didn’t stop him from pitching at two minor league levels — Double-A and Triple-A — before ending the season in the Mariners’ big league rotation. The young right-hander made three starts in The Show, two of which came against the lowly Houston Astros.

The Scouting Report: Walker has dominating stuff. The right-hander’s velocity on his fastball sat at 95 mph in his three MLB starts thanks in part to his quick arm action. He’s developed a hard cutter that he throws 88-92 mph and it definitely has a chance to be a plus pitch for him. Both Walker’s curveball and changeup need further refinement and he needs to do a better job of finishing off his pitches. The young pitcher’s delivery is very upright and I’d like to see a little more follow through with his delivery to mitigate the strain on his shoulder. Walker could probably use another two or three months of seasoning in the minors but he could survive in The Show on his raw stuff, which is good enough for him to get away with some mistakes.

The Year Ahead: Walker has positioned himself well to be considered for a spot in the Mariners’ opening day starting rotation. His strongest competition will likely come from fellow youngsters James Paxton and Brandon Maurer. Even if he opens the year in the minors, Walker should see the Majors by the all-star break.

Final Thoughts by Jason Churchill: Walker is now in the final stages of his development from prospect to big-league starting pitcher, but there are years of refinement ahead if he’s to turn into a No. 1. Walker’s athleticism helps him keep his delivery free and easy, which in turn allows him to work off the mid-90s heater, and use his cutter to keep batters off an underdeveloped set of offspeed pitches. More consistency with his changeup and curveball are necessary, but he’s among the very best pitching prospects in the game, thanks to the life on his fastball and his maturity after just three years in pro ball. He’s ready for the show after a cup of coffee in 2013.


#2 D.J. Peterson | 60/R (3B)

21 230 63 11 13 20 42 1 .303 .365 .553 .417

The Year in Review: Peterson, an Arizona native, was drafted 12th overall in the 2013 amateur draft after an outstanding college career at the University of New Mexico. His immense potential was on full display during trips to both the Northwest and Midwest Leagues but his season was cut short by an ugly beaning that result in his jaw being wired shut after surgery. Peterson ended his first pro season with a batting average of more than .300 and an OPS of .918 in 55 games.

The Scouting Report: Peterson displays good bat speed, which helps him compensate for his open stance and allows him to get to pitches on the outer half of the plate. Regardless, he may continue to get challenged away and will have to show a willingness to go the other way and utilize the whole field. He has a fairly short batting stroke for a power hitter and the ball jumps off the bat. Defensively, he’s a fringe-average defender with a strong arm who may eventually be moved to a corner outfield position.

The Year Ahead: Beanings can take both a physical and a mental toll on a player so Peterson will no doubt be watched closely in the spring. Prior to the injury, he was probably headed to High-A ball to open the 2014 season but the organization may now want to bring him along more slowly and return him to Low-A ball, at least for a month or two. Either way, if he’s back to his old self, he should be a quick mover.

Final Thoughts by Jason Churchill: Peterson can flat out hit, and the Mariners drafted him to do so, despite the likelihood that he’ll have to move across the field and play first base rather than his natural position at the hot corner. He’s a year or two from the big leagues, but Peterson shouldn’t take long to break into the majors as a Billy Butler type bat, perhaps with more home run power, and a much better chance to play in the field regularly. It wouldn’t be surprising if he saw Safeco Field in September of 2014 with shot to make the 25-man roster out of spring training the following year.


#3 James Paxton | 55/MLB (P)

24 24.0 7.88 2.63 59.1 % 1.50 3.26 3.08 1.1 0.5

The Year in Review: Consistency problems continued to plague Paxton in 2013. He was lights-out at times, while at other times his command played games of cat-and-mouse. The Canadian left-hander actually pitched better in the Majors than he did in the minors (partly owing perhaps to the small-sample size) and put himself into a good position for the 2014 season.

The Scouting Report: Paxton has good stuff for a lefty. He has easy velocity and the fastball sits in the 92-96 mph range with arm-side run. His curveball shows potential as a plus pitch but it needs to be more consistent. I’ve seen some very good changeups from him but he throws the offering a little too hard at 86 mph. When his fastball is 96 mph that’s fine, but there isn’t enough separation if his heater is sitting 92. He’s at his best when he can command his offerings down in the zone and can get into trouble when he elevates. Paxton has a long arm action but his delivery has some flair to it, which creates some distraction for the hitters.

The Year Ahead: Paxton recently turned 25 years old so he’s more mature than most of the pitchers on this list. He’s a favorite to earn a spot in the opening day starting rotation but he’ll have to become more consistent if he’s going to hold down the job. After finishing just shy of 170 innings pitched in 2013, Paxton could come close to the 200-inning mark in 2014 — especially if he’s more efficient with his pitch count.

Final Thoughts by Jason Churchill: At mid-season, scouts were talking about Paxton as a reliever, or at best a back-end starter who can’t throw enough strikes to get to 200 innings, despite the plus fastball and curveball. Since then, Paxton has compacted a long-levered delivery which has helped him pound the strike zone and take advantage of his raw stuff. Surprisingly, he’s terrific at holding runners — despite the slower actions from set to release — and he flashed frontline abilities after a big-league call-up in September. He’s a future No. 2 starter if he keeps it all together, carrying a No. 4 floor, and keeping a future in the bullpen at bey as long as he throws strikes.


#4 Victor Sanchez | 60/A- (P)

18 20 20 113.1 106 4 6.27 1.43 2.78 2.87

The Year in Review: The young pitcher was a workhorse in 2013 and compiled 113.1 innings in 20 starts at the Low-A ball level. His skills were on full display when threw a no-hitter in July against Toronto’s Midwest League affiliate.

The Scouting Report: The 18-year-old hurler has well-above-average control for his age but needs to improve the command of his heater in the strike zone. Sanchez’s arm action naturally gives hitters a long look at the ball out of his hand. His changeup is his second-best offering but his breaking ball needs polish and he needs to trust it more. Built like tank, Sanchez will have to watch his conditioning as he ages to avoid losing his flexibility. He’s already very upright in his delivery and isn’t the most athletic while fielding his position.

The Year Ahead: Sanchez will face a stiff test when he’s tossed to the wolves as a 19 year old in the California League. The assignment should challenge him to work down in the zone a little more and trim his fly-ball tendencies. It’s not out of the realm of possibility that he could see Double-A by the end of 2014.

Final Thoughts by Jason Churchill: Sanchez is a strike-thrower with average to slightly above-average velocity with his fastball, but good pitchability and a consistent delivery. There are some mechanical fixes to be made, but the kid knows how to pitch and is adept at mixing in a two-plane slurve and changeup with regularity, and getting called strikes with each early in counts. There’s no physical projection to be seen with Sanchez — he’s listed at 6-feet and 255 pounds — but he’s fairly polished and could serve as a No. 4 starter as early as mid-2015.


#5 Danny Hultzen | 60/AAA (P)

23 7 7 35.2 22 1 10.60 1.77 2.02 1.88

The Year in Review: There were some high-profile injuries in the Mariners’ system in 2013 and Hultzen’s was probably the worst. The southpaw ended the 2012 season with control/command woes (43 walks in 48.2 Triple-A innings) and was then haunted by shoulder problems throughout the 2013 season. He made just seven starts on the season and had surgery to repair his rotator cuff and labrum at the beginning of October.

The Scouting Report: Before the injury, Hultzen was clearly the top southpaw pitching prospect in the minor leagues. His across-the-body delivery — which adds deception and can improve pitch movement — could have exacerbated the shoulder problems. When healthy, the young pitcher shows a slightly-above-average fastball that works in the low-90s and can touch 94-95 mph. His changeup was an above-average offering, while his slider was developing at a slightly slower pace.

The Year Ahead: Clearly it’s a big blow to the organization to lose a player of Hultzen’s talent level to injury. The second overall selection in the 2011 amateur draft, the lefty could miss all of the 2014 season while rehabbing from the intensive surgery. Injuries to the rotator cuff and labrum ruined a lot more careers than those to the elbow.

Final Thoughts by Jason Churchill: Hultzen pitched very well in each of his seven starts a year ago, and it appeared he’d figured out his mechanics enough to throw strikes consistently after a long bout of control problems the second half of 2012. He’ comfortable in the 89-91 mph range with his four-seam fastball, and employs a slider versus left-handed batters and a curveball against right-handed batters. His changeup is his best pitch, often using it to get swings and misses. Unfortunately, those mechanics — he throws across his body with gross severity — likely contributed to his current medical situation, which includes shoulder surgery that will keep him out until the 2015 season. Hultzen’s ceiling as a soft No. 2 or solid No. 3 may be in jeopardy as a result.


#6 Tyler Pike | 55/A- (P)

19 22 22 110.1 73 5 7.34 4.65 2.37 3.73

The Year in Review: Another talented left-handed pitcher on this list, Pike is proving to be a steal as a former third round draft pick (2012) out of a Florida high school. The southpaw more than held his own as a teenager in the Low-A Midwest League. He allowed just 73 hits in 110.1 innings and posted a 2.37 ERA but struggled to throw strikes at times.

The Scouting Report: Pike shows good athleticism while flashing a solid repertoire. His heater works in the high 80s to low 90s, his curveball shows potential but needs to be tightened up and his changeup came along nicely in 2013. The young lefty utilizes an over-the-head delivery with a high leg kick from the full windup so it’s easy to see why he struggles with both his command and control. He tries to guide the ball at times, which also hurts his command. On the plus side, though, his delivery helps him hide the ball, which gives hitters less time to identify the pitches coming out of his hand. Pike needs to do a better job of commanding the inner half of the plate against right-handed hitters.

The Year Ahead: The young pitcher will move up to High-A ball as a 20 year old but the offense-happy California League can eat up and spit out pitchers before they know what hit them. As a result,Pike may only spend a couple month there before being moved up to Double-A. It’s an aggressive timetable for such a young pitcher but he should have both the talent and the maturity to handle the assignments.

Final Thoughts by Jason Churchill: Pike is an athletic Tom Glavine clone southpaw, and one who could move quickly once he settles in on a set of mechanics that work for him. As is, Pike offers upper-80s velocity — touching the low-90s — with an above-average changeup and curveball. The upside here is limited, but the probability he starts in the Majors, sans injury, is fairly high, and despite the lack of ideal stature – 6-foot-1 and 185 pounds or so — Pike’s stuff suggest he could be a terrific No. 4 or perhaps even a No. 3 if all goes right. He’ll start 2014 with a chance to set himself up for a big-league appearance in 2015, though he’s got a lot of work to do.


#7 Edwin Diaz | 55/R (P)

19 13 13 69.0 45 5 10.30 2.35 1.43 2.81

The Year in Review: Just 19 years old, Diaz more than held his own in the advanced-rookie Appalachian League. His above-average control was on full display when he walked just 18 batters (and struck out 79) in 69.0 innings. Diaz also showed some ice in his veins by being extremely tough to hit once batters reached base and got into scoring position.

The Scouting Report: Diaz displayed above average control for his age in 2013 and his command has also took a step forward, although it was inconsistent at times. The Puerto Rico native works with his fastball in the low to mid 90s. His breaking ball improved significantly in 2013, which helped him overpower hitters in the low minors but the changeup needs further refinement. Extremely skinny when he signed in 2012, Diaz has since added on about 20 pounds and has room to add even more in an effort to improve his durability and perhaps add another tick or two to his heater.

The Year Ahead: Diaz is ready for full-season ball and could handle a jump in innings-pitched into the triple-digits. He’ll probably spend almost a full season in Low-A ball but he could get a taste of High-A action in an effort to prepare him for a full season in the potent California League in 2015.

Final Thoughts by Jason Churchill: Diaz falls into the give-him-water-and-food-and-watch-him-grow category, and he’ll need to continue to add good weight and refine his changeup to progress beyond the high minors, but the fastball-curveball combination are among the better ones in the system and the safe bet is that the Puerto Rico native is at least a dominant, late-inning reliever. There’s still a good chance he stays in the rotation, however, but there is a lot to learn and he’s likely three years from the big leagues, giving him plenty of time to study.


#8 Luiz Gohara | 55/R (P)

16 6 6 21.2 22 1 11.22 3.74 4.15 2.83

The Year in Review: The Dodgers’ young phenom Julio Urias made a lot of headlines by pitching in Low-A ball at the age of 16, but he wasn’t the only 16-year-old that was playing North American professional baseball in 2013. Gohara was pitching a few levels down in the advanced-rookie Appalachian League but the Brazilian arguably has a higher ceiling than the Mexican teenager. The Mariners southpaw prospect made just six starts during the 2013 season thanks to his battles with a persistent shoulder injury.

The Scouting Report: Gohara has an excellent feel for pitching for his age and experience level. The left-hander’s fastball works in the low 90s and his breaking ball has the makings of developing into a plus pitch. It’s been referred to as both a curveball and a slider, perhaps because he’s able to vary the speeds on the offering. His changeup needs the most work but it has its moments. Gohara should provide above-average command and control as he matures due to his smooth, repeatable delivery. To date, he’s done a nice job leveraging his height to create a downward angle on his offerings, which has produced above-average ground-ball rates.

The Year Ahead: Assuming he’s healthy, Gohara is talented enough to open the year in Low-A ball. The organization, though, is more likely to hold him back in extended spring training before deciding upon his ultimate destination for 2014. With just 21.2 innings thrown in 2013, he’s not likely to see a huge increase in his workload.

Final Thoughts by Jason Churchill: Gohara is projectable, strong and possesses very sound mechanics for a teenager, and the M’s are hoping the velocity comes as he matures as a pitcher — he’s already in the 220-pound range, so it’s not about filling out and growing physically. The southpaw has drawn rave reviews for his work ethic and mature approach, which bodes well for his future. He’s years from the big leagues, but should hit full-season ball in 2014.


#9 Chris Taylor | 50/AA (SS)

22 695 185 32 9 90 132 43 .312 .403 .452 .387

The Year in Review: You’d think the Mariners’ system would be devoid of any talented shortstop prospects after it graduated both Nick Franklin and Brad Miller to The Show in 2013… but you’d be wrong. Taylor, a two-year pro, was a teammate of Danny Hultzen’s at the University of Virginia and may soon pass him on the prospect depth chart if the talented lefty hurler cannot fully bounce back from shoulder surgery. Taylor, 22, saw time in both High-A and Double-A ball before hitting well in 18 Arizona Fall League games.

The Scouting Report: Taylor, 23, employs a quiet setup at the plate as well as a patient approach, which leads to high walk totals. He could stand to be quicker to the ball with bat, though, which would help him cut down on the strikeout totals that are high for a player with a modest power output. With a little more meat on his frame, he could hit for a more authority and turn some of his doubles and triples into home runs. Taylor has above-average speed and is a smart base runner who nabbed 38 bags in 43 attempts. Defensively, he’s an above-average shortstop with good range, soft hands and a strong arm, who has also seen time at second base. He should be able to handle either position at the big league level.

The Year Ahead: After a strong showing in the AFL, Taylor could be headed for an opening day assignment to Triple-A, although some more time in Double-A would not be the worst thing for his development. The young infielder still has some polish to add to his overall skill set but he could be in the Majors by the end of the 2014 season, which could be the start of a middle-infield logjam.

Final Thoughts by Jason Churchill: Taylor is an all-glove shortstop who is doing a great job at shoving that label up the backsides of clubs who passed on him for that reason. The hands and feet are terrific and Taylor’s arm strength grades out in average to above-average range, suggesting he’s at least a utility candidate in the majors. He’s made some swing adjustments in his quick ascent through the minors, but more are needed if he’s to hit for enough extra-base power to warrant any consideration for a long-term starting role. His patience and all-around plate skills are superb, but he will strike out, and that will be a challenge for him in Triple-A, which is where he’ll start 2014.


#10 Austin Wilson | 55/R (OF)

21 226 49 11 6 17 42 2 .241 .319 .414 .348

The Year in Review: Wilson was popped by the Mariners with the 49th overall selection in the 2013 amateur draft after a solid career at Stanford University. Assigned to the Northwest League, the athletic outfielder got off to a slow start through June and July. Wilson heated up in August and just missed hitting .300 for the month. He also hit five of his six home runs that month (21 games) while significantly improving his contact rate.

The Scouting Report: Wilson is the type of player that causes scouts to say, “He looks like a baseball player.” His best tools are his arm (plus), speed (above average) and his outfield defense (above average). His bat (fringe-average) and useable power (fringe-average) need the most work. Wilson’s frame hints at his raw power potential but he needs to improve his pitch recognition, shorten his swing, and generally become more consistent with his swing mechanics. Even if he doesn’t hit for a high average, Wilson should be an impact player in the outfield — most likely in right field — and at the plate if he taps into the power to his pull side.

The Year Ahead: Wilson is a little more raw than your typical highly-drafted player from the college ranks so it may behoove the organization to go easy on the talented prospect in his first full pro season. He should get his feet wet in Low-A ball but could force his way to High-A in the second half of the year. His MLB ETA is probably 2016, or possibly late 2015.

Final Thoughts by Jason Churchill: Wilson was an aim-high second-round draft pick last June and the Stanford product struggled mightily for the first half of his stint in the short-season Northwest League. That changed dramatically in late July when Wilson went on a tear, cutting down the strikeouts and adding regular power to the results. His swing still needs work, but he’s fixed the flat-bat and dead-hand start, and in the end is a solid bet to hit .260 with 25 home runs. He’s a big fella at more than 240 pounds, but he’s athletic and has a plus throwing arm that will fit nicely in right field at the Safe. He’s not on the fast track like Peterson, but the upside could warrant all-star consideration.

The Next Five:

11. Gabriel Guerrero, OF: The young Dominican outfielder doesn’t turn 20 until December but he performed well in full-season ball given his age. At the plate, the nephew of Vladimir Guerrero looks similar to his uncle. He often expands the zone, leading to low walk rates and high strikeout rates. His swing can get long but his above-average bat speeds helps him compensate.Guerrero hit just four home runs this past season but has above-average raw power.

12. Tyler Marlette, C: Marlette made huge strides behind the plate in 2013, which caused his prospect value to increase significantly. The 20-year-old Florida native is a strong hitter. He isn’t afraid to take the pitch where it’s offered and go the other way. He showed flashes of his raw power potential in ’13but needs to be a little more selective to continue having success as he reaches the upper levels of the minors.

13. Julio Morban, OF: Drafted out of the Dominican Republic as a highly-regarded amateur, Morban’s development has been slowed somewhat by injuries and he played in a career-high 86 games in 2013. His open stance resembles a left-handed-hitting Tony Batista. The young hitter has above-average bat speed that helps him get to pitches on the outer half of the plate and it allows him to produce power to all fields.

14. Patrick Kivlehan, 3B: A senior sign out of Rutgers University, the 23-year-old hitter has hit more than .300 in his two pro seasons which is impressive given that he barely played baseball in college, thanks to a focus on football. He still has some rough edges around his game and he’s still looking to tap into his power potential. He’s been playing third base exclusively but may eventually move to first base or a corner outfield position.

15: Ketel Marte, SS: Marte recently turned 20 and had a solid full-season debut in the Midwest League where he showed the potential to develop into a solid No.2 hole hitter. He handled the bat well as a teenager in 2013 and made above-average contact, even though it negatively impacted his walk rate. He also needs to let poor pitches go by without offering at them. The switch-hitter has good actions in the field but makes a lot of youthful mistakes.

Marc Hulet has been writing at FanGraphs since 2008. His work focuses on prospects and fantasy. Follow him on Twitter @marchulet.

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10 years ago

I bet Paxton probably has an arm up on Walker based on his starts last season.

Who is the better long term pick up?

10 years ago
Reply to  FeslenR

Walker, and it isn’t even close.

Marc Hulet
10 years ago
Reply to  FeslenR

Definitely Walker.

10 years ago
Reply to  Marc Hulet

Walker is much younger, has the better mechanics and always has, and has the higher ceiling. Yet I wouldn’t be the least surprised if Paxton doesn’t produce the better results for much of the next 5-6 years. Paxton has stuff. He’s all focus and business on the mound, and doesn’t let adversity affect him. ALL his pitches have plus potential. I’m not saying tha Paxton gets that out of them every outing or every year, but he has the ability to throw a terrific pitch every time. I was there for his start against Tampa Bay at Safeco: he threw 98 on his final pitch.

Paxton came from a cold weather province. Then missed a full year of development due to the drafting snafu (and didn’t Toronto’s higher up guy sandbag him or what?). Paxton’s been a big guy with long mechanics who needed time to get himself into a compact set up over his stride, but how he’s got deception, and negates the running game also.

James Paxton is simply a stud who has been underrated from the get-go, and remains so. Yes, he’s 25, has never been pitch efficient before, and his mechanics might desert him. When he’s on, Paxton may match up to the best pitchers in the game. It will take a year or two of that kind of outcome for ‘perceptions’ to catch up to outcomes.

10 years ago
Reply to  FeslenR

I was more impressed with Paxton than Walker in watching their major league starts. But I didn’t watch every pitch of every start. Paxton looked like he could be a dominating lefty. But Walker is younger and is more hyped.