Baseball’s hot stove season got off to an uncharacteristically early start this time around, as the Rays and Mariners made a “challenge” type of trade, centering around two young, inexpensive players with plenty of years of control remaining, shortstop Brad Miller and starting pitcher Nate Karns. I agree with most of Dave Cameron’s thoughts in the immediate wake the trade: one’s opinion of this deal largely depends on whether one believes Miller is truly a regular shortstop, and whether ones believe Karns is a long-term rotation fixture.
While there are no absolutes in the projection of either player’s future, and there are other players in the deal who will eventually impact the net result, this trade will likely come down to Miller vs. Karns. What does the weight of the evidence suggest at this point in time regarding those two players?
Full disclosure: I was a member of the Mariner front office when Miller was selected in the second round of the 2011 draft out of Clemson, and I had significant input in his selection. I am not shy about identifying myself as a Brad Miller supporter from way back. He stood out from both a scouting and analytical standpoint; he was athletic enough to lead us to believe he would be able to stay at shortstop over the long haul and meet the steep requirements of the position at the major league level. He also had a superior offensive profile for a middle infielder: he never struck out, had projectable power with a wooden bat, and was able to hit same-handed pitching.
His junior year college numbers, which were strong across the board, were actually undercut by a single poor weekend in which he came back to soon from a minor hand injury. In our draft room, Brad Miller was considered a first round pick, and when he was sitting there for us in the second round, we were ecstatic to pull the trigger.
Miller was a hitting machine in the minor leagues, batting an eye-catching .334/.409/.516 in 999 plate appearances. While he did spend a little less than half of that time at the High-A High Desert launching pad, he performed almost exactly as well afterward at Jackson in the pitcher-friendly Double-A Southern League, and even better in a brief trial at Triple-A Tacoma.
Each season, I compile my own ordered list of minor league position player and starting pitcher prospects, based on production and age relative to league and level. This list is not adjusted for position scarcity, so the non-Carlos Correa shortstops rarely reside at the top. Miller qualified for the list in 2012 and 2013, all the way up at #39 and #14, respectively. While many incumbent major league shortstops fared well on my list on their way to the majors, only three — Correa, Xander Bogaerts and Jose Reyes — had higher peak rankings than Miller.
Miller moved in as the Mariners’ primary shortstop early in the summer of 2013, spending about two solid seasons in that role. Over that period, he has been a league average offensive player by any measure, posting a career 100 wRC+ and 101 OPS+. That might not sound particularly exciting, but only a third of the 30 primary MLB shortstops reached that mark in 2015. An everyday shortstop with a major league average bat, with multiple years of team control remaining, and who just turned 26 — an age when plenty of careers have leapt to the next plateau — is a tremendous asset.
What about that next plateau? Many Mariner position player prospects have not delivered on early promise at the major league level in recent seasons. Dustin Ackley, Mike Zunino and Miller are three examples of players who started strong, but weren’t able to respond after the league adjusted to them. Miller’s relatively poor .221/.288/.365 line in the 2014 campaign was marked by a spike in his strikeout (K) rate and an ongoing tendency to pull the ball, something that wasn’t part of his game in the minor leagues. Ackley and Zunino’s struggles were marked by the same tendencies.
Miller showed some signs of improvement in 2015, however. His pull rate cratered from 39.6% to 32.9%, while his oppo rate spiked from 24.1% to 31.7%. This meant that opposing clubs could only overshift him in the infield at their own risk. More importantly, Miller simultaneously cut his K rate while improving his batted ball authority last season. While his 20.3% K rate is still well lower than his 2013 mark of 15.5%, it was down from 23.1% in 2014, into the league average range. His walk rate has trended positively throughout his career, and at 9.5%, was over one-half standard deviation above the average of AL regulars in 2015.
His average ball-in-play (BIP) exit speed in 2015 was 90.7 mph, over one-half standard deviation above the AL average. He had previously been in the league average range in 2014, and over one-half standard deviation below league average in 2013. More authority, less pulling, more contact, more walks… all positive trends for his near-term offensive health.
His one remaining clear offensive weakness is his performance against same-handed pitching: he’s a .226/.273/.302 career major league hitter versus lefties. His trend toward more contact and better use of the entire field suggests that he should improve in this area at least somewhat moving forward, as does his career minor league mark of .268 against southpaws.
How about his defense? Some baseball people I greatly respect don’t see him as a long-term shortstop. His actions are long and a bit unorthodox, but his results have hovered around league average, using both traditional and new-age metrics. His arm strength is above average, though he has been inconsistent with his accuracy and release at times. For me, he is a league average shortstop with the glove, somewhere between the 45th and 55th percentile. With a bat that can approach 120 wRC+. I’ll take that in a heartbeat.
Miller was done no favors by the Mariners last season. Without any previous experience, he became the club’s center fielder of the present, with predictably poor results. They now see Ketel Marte as their future at shortstop, and while he is a smoother, more conventional defender, he struggles to elevate the baseball with any authority and thus has a much lower offensive ceiling.
Let’s now turn our attention to Nate Karns. He always possessed superior arm strength, but struggled about as much as a mid-90s mph college right-hander could, posting an 8.46 ERA and allowing over two baserunners per inning — you read that right — after transferring from North Carolina State to Texas Tech in 2008. Even in his draft year of 2009, he righted the ship only somewhat, recording a 5.47 ERA and allowing over a runner and a half per nine innings. In three college seasons, he allowed 5.7 walks per nine innings and averaged barely four innings per start. That’s right, four.
Despite his superior arm strength, Karns drifted all the way down into the 12th round of the 2009 draft, where he was selected by the Nationals. Before he ever pitched an inning as a pro, he underwent significant shoulder surgery, which cost him the entire 2010 season. Karns immediately harnessed his stuff once fully healthy, dominating A-ball competition in his first two pro seasons. That was the good news. The bad news: entering 2013, he was 25 years old, and hadn’t yet faced Double-A competition. As a result, he never qualified for my minor league starting pitcher prospect list.
After he whiffed over a batter per inning in the Eastern League in 2013, the Rays pounced, flipping three players, including big league backup catcher Jose Lobaton, to the Nats for Karns. After an uneven but healthy Triple-A campaign in which he posted a 5.08 ERA in the relatively pitcher-friendly International League, Karns competed for and won a spot in the Rays’ rotation last spring.
To get a better feel for his 2015 season, let’s examine Karns’ plate appearance outcome frequency and relative production allowed by BIP type data:
While it is true that Karns was able to transfer his ability to strike hitters out to the major league level (81 K rate percentile rank), the high walk rates that dogged him throughout his amateur and minor league careers followed as well (88 BB rate percentile rank). Only two pitchers who qualified for the AL ERA title had higher BB rates, Trevor Bauer and Hector Santiago. The rest of his frequency profile is pretty nondescript; he showed a moderate fly ball tendency (71 percentile rank), and his pop up and liner rates were squarely in the league average range.
Let’s toss in a scouting angle here. Karns’ swing-and-miss rate of 9.2% was below the average of AL ERA qualifiers (9.7%), which might lead one to believe that his K rate might not have staying power. That is not my concern with Karns. Eno Sarris has written extensively about the improvement in Karns’ changeup, which is part of the reason for the new Mariner’s reverse split in 2014. While the Mariners’ citation of Karns as a “proven strikeout pitcher” in the aftermath of the deal is a bit overstated — his K rate and K/9 were both just over one-half standard deviation above league average, not exactly in the stratosphere — I wouldn’t expect material short-term deterioration of his K rate.
A fairly vanilla frequency profile tells us only so much. Karns’ relative production allowed by BIP type data will give us a broader perspective of his 2015 performance:
|Karns||AVG||OBP||SLG||REL PRD||ADJ PRD||ACT ERA||CALC ERA||FIP||TRU ERA|
The actual production allowed on each BIP type is indicated in the batting average (AVG) and slugging (SLG) columns, and is converted to run values and compared to MLB average in the REL PRD (or Unadjusted Contact Score) column. That figure is then adjusted for context, such as home park, team defense, luck, etc., in the ADJ PRD (or Adjusted Contact Score) column. For the purposes of this exercise, sacrifice hits (SH) and flies (SF) are included as outs and hit by pitchers (HBP) are excluded from the on-base percentage (OBP) calculation.
The first, most noticeable aspect of Karns’ profile is the total absence of sub-100 numbers for any of the BIP types. In other words, Karns allowed average to harder than average contact across the board. Of particular concern are the 113 and 126 liner and grounder Adjusted Contact Scores. The liner mark equaled the highest of AL ERA qualifiers, posted by Alfredo Simon, while the grounder mark exceeds those of all 2015 AL ERA qualifiers.
Karns’ average pop-up tendency and fly ball authority allowed keeps his overall Adjusted Contact Score in check somewhat at 104; add back the Ks and BBs, and his “tru” ERA of 3.70 is a close match for his ERA, and better than his 4.09 FIP.
Broad conclusions re: Karns? My largest concerns are that he is now 28 years old, has never pitched more than 157 innings in a season in the majors or minors, and ended 2015 on the disabled list with a forearm strain. He’s never been as much as a six-inning starter, even in the minors, and is basically good for two times around the order.
He is the type of pitcher you target from an organization in a relatively minor trade, like the one that landed him in Tampa in the first place. This is not an established major league starter upon whom you can rely, at least not yet. It’s certainly not one that you accept in return for an inexpensive, left-handed-hitting, above average — with more upside — major league shortstop. I would take Erasmo Ramirez, who the Mariners sent to Tampa for pennies on the dollar, over Karns; while he might not have the latter’s upside, he has a better chance of being a reliable MLB starter on an ongoing basis.
On balance, this trade likely is more representative of the end of the previous management team’s era in Seattle, not the beginning of the current one’s. Miller was devalued before Jerry DiPoto took over, and an argument can be made that the new GM is simply closing the books and making the best of it going forward. In fact, there’s at least a chance that Triple-A outfielder Boog Powell could ultimately tip the scales on this deal in the Mariners’ favor. As their careers evolve elsewhere, however, Mariner fans might wonder what could’ve been if players as varied as Ackley, Miller, Ramirez, and perhaps Zunino had reached their potential for the club that drafted them.