KATOH Projects: Seattle Mariners Prospects

Previous editions: ArizonaBaltimore / Boston / Chicago AL / Chicago NL / Cincinnati  / Cleveland / Colorado / Detroit / Houston / Kansas City / Los Angeles (AL) / Los Angeles (NL)Miami / Milwaukee / Minnesota / New York (AL) / New York (NL) / Philadelphia / Pittsburgh / San Diego / San Francisco.

Yesterday, lead prospect analyst Dan Farnsworth published his excellently in-depth prospect list for the Seattle Mariners. In this companion piece, I look at that same Seattle farm system through the lens of my recently refined KATOH projection system. The Mariners have the 24th-best farm system in baseball according to KATOH.

There’s way more to prospect evaluation than just the stats, so if you haven’t already, I highly recommend you read Dan’s piece in addition to this one. KATOH has no idea how hard a pitcher throws, how good a hitter’s bat speed is, or what a player’s makeup is like. So it’s liable to miss big on players whose tools don’t line up with their performances. However, when paired with more scouting-based analyses, KATOH’s objectivity can be useful in identifying talented players who might be overlooked by the industry consensus or highly-touted prospects who might be over-hyped.

Below, I’ve grouped prospects into three groups: those who are forecast for two or more wins through their first six major-league seasons, those who receive a projection between 1.0 and 2.0 WAR though their first six seasons, and then any residual players who received Future Value (FV) grades of 45 or higher from Dan. Note that I generated forecasts only for players who accrued at least 200 plate appearances or batters faced last season. Also note that the projections for players over a relatively small sample are less reliable, especially when those samples came in the low minors.

1. Boog Powell, OF (Profile)

KATOH Projection: 4.0 WAR
Dan’s Grade: 45+ FV

Powell split 2015 between Double-A and Triple-A, and hit a respectable .295/.385/.392. He did an excellent job of controlling the strike zone, striking out just 15% of the time, while walking nearly as often. Powell pairs that plate discipline with a modicum of power and plus speed. He swiped 18 bases last year, and has primarily played centerfield in the minors. Powell’s tools scream “fourth outfielder,” but his numbers suggest he could be destined for an everyday gig.

Boog Powell’s Mahalanobis Comps
Powell Name Proj. WAR Actual WAR
1 Michael Bourn 2.7 14.0
2 Omar Ramirez 5.5 0.0
3 Darin Erstad 4.0 21.9
4 Brian Giles 3.6 14.4
5 Jason Conti 3.2 1.2
6 Kenny Kelly 2.6 0.0
7 Rob Katzaroff 2.6 0.0
8 Terrence Long 4.9 5.1
9 Dan Peltier 3.8 0.0
10 Gregor Blanco 3.3 7.4

2. Edwin Diaz, RHP (Profile)

KATOH Projection: 3.9 WAR
Dan’s Grade: 55 FV

Diaz split time between High-A and Double-A last year, and finished with a 3.32 FIP and impressive 15% strikeout rate. Don’t let his 4.22 ERA in Double-A fool you: Diaz’s 3.22 FIP suggests he pitched very well at the level. Twenty-one-year-olds who pitch very well in Double-A usually turn out to be pretty good.

Edwin Diaz’s Mahalanobis Comps
Rank Player Proj. WAR Actual WAR
1 Francisco Liriano 4.5 14.0
2 Sun-Woo Kim 3.2 2.4
3 Ricky Nolasco 3.9 14.4
4 Jaime Garcia 3.7 12.7
5 Hector Trinidad 3.2 0.0
6 Jordan Zimmerman 3.8 17.6
7 Brad Radke 4.4 25.1
8 Ted Lilly 4.4 8.2
9 Will Inman 3.6 0.0
10 Angel Guzman 4.2 0.9

3. Drew Jackson, SS (Profile)

KATOH Projection: 3.0 WAR
Dan’s Grade: 50 FV

Jackson absolutely raked after the Mariners took him in the 5th round out of college last year. The shortstop slashed .358/.432/.447 in 59 games in the Northwest League, and stole an eye-popping 47 bases. Before you get too excited, I’ll point out that Jackson played most of those games as a 22-year-old against younger competition. I’ll also point out that he relied heavily on .414 BABIP. But still: you couldn’t ask for much more from Jackson in his pro debut.

4. Tyler O’Neill, OF (Profile)

KATOH Projection: 2.7 WAR
Dan’s Grade: 40 FV

An all-or-nothing slugger, O’Neill crushed 32 homers in High-A last year, but did so with a 31% strikeout rate. O’Neill did swipe 16 bases last year, so he isn’t completely one-dimensional. But hitters with strikeout rates over 30% rarely pan out, especially when those Ks aren’t balanced out by walks.

5. Adrian Sampson, RHP (Profile)

KATOH Projection: 2.4 WAR
Dan’s Grade: Unranked

Sampson spent all of last season at the Triple-A level. He opened the year with the Pitates organization before coming over to the Mariners in the J.A. Happ deal at the deadline. Sampson’s numbers weren’t great overall, though he did manage a 4% walk rate. A 4.76 ERA and 3.54 FIP with unremarkable strikeout numbers doesn’t sound particularly impressive, but relatively few 23-year-olds are capable of such a performance at Triple-A.

6. Joe Wieland, RHP (Profile)

KATOH Projection: 2.1 WAR
Dan’s Grade: Unranked

Although he debuted in the majors way back in 2012, Wieland is still a prospect here in 2016. Once a promising young player in the Rangers system, Wieland’s career has been derailed by injuries. But he showed glimpses of his former self last year when he posted a 3.52 FIP as a starter for the Dodgers’ Triple-A affiliate. He figures to have a future in the big leagues, even if it’s an unglamorous one.

7. Tyler Marlette, C (Profile)

KATOH Projection: 2.0 WAR
Dan’s Grade: Unranked

Marlette enjoyed offensive success his first few years in the minors, but hit just .239/.291/.380 between High-A and Double-A last year. His future doesn’t look as bright as it once did, but he’s still a catcher who’s shown offensive promise in the recent past.


1-2 WAR Prospects
Rank Player Position KATOH WAR Dan’s FV
8 Luiz Gohara LHP 1.7 45
9 Luis Liberato OF 1.5 40
10 Tyler Smith SS 1.4 35+
11 Ian Miller OF 1.3 35+
12 Zack Littell RHP 1.3 Unranked
13 Rayder Ascanio SS 1.3 35+
14 Cody Martin RHP 1.2 Unranked
15 D.J. Peterson 1B 1.2 45+
16 Shawn O’Malley 2B 1.1 Unranked
17 Marcus Littlewood C 1.1 Unranked
18 Paul Fry LHP 1.0 40+
19 Dario Pizzano OF 1.0 Cistulli’s Guy

Zack Littell posted encouraging strikeout and walk numbers in Low-A last year, and did the same in Rookie-ball in 2014. Cody Martin is already 25, but he struck out a good number of batters as a starter in Triple-A. As a 28-year-old, Shawn O’Malley isn’t really a prospect, but he’s succeeded in Triple-A the past two years, which suggests he be a serviceable major leaguer. Marcus Littlewood hit a passable .231/.305/.390 as a 23-year-old catcher in Double-A last year.


Remaining 45+ FV Prospects
Name Position KATOH WAR Dan’s FV
Ryan Yarbrough LHP 0.5 45+
Alex Jackson OF 0.2 45

Ryan Yarbrough held his own in A-Ball last year, but KATOH dings him for being 24 already. Alex Jackson’s projection should be self explanatory: he was all-sorts of terrible last year, especially in he strikeouts department.

We hoped you liked reading KATOH Projects: Seattle Mariners Prospects by Chris Mitchell!

Please support FanGraphs by becoming a member. We publish thousands of articles a year, host multiple podcasts, and have an ever growing database of baseball stats.

FanGraphs does not have a paywall. With your membership, we can continue to offer the content you've come to rely on and add to our unique baseball coverage.

Support FanGraphs

Chris works in economic development by day, but spends most of his nights thinking about baseball. He writes for Pinstripe Pundits, FanGraphs and The Hardball Times. He's also on the twitter machine: @_chris_mitchell None of the views expressed in his articles reflect those of his daytime employer.

newest oldest most voted
Nathaniel Dawson
Nathaniel Dawson

I absolutely love that you do this, Chris. I really believe in an all-stats approach to evaluating minor leaguers as a perfect complement to scouting based analysis.