TD Top Prospects: #8 Kohl Stewart
Age: 22 (DOB: 10/7/94)
2016 Stats (A+/AA): 143.2 IP, 2.88 ERA, 91/63 K/BB, 1.34 WHIP
2016 Ranking: 9
National Top 100 Rankings
BA: NR | MLB: NR | ESPN: 87 | BP: NR
At St. Pius X High School in Houston, Stewart was a legendary athlete. A star quarterback, he was widely recruited before signing a letter of intent with Texas A&M. Calling signals on Saturday for the Aggies was undoubtedly a dream of his while growing up 90 minutes away from campus, but ultimately he decided to follow his golden right arm in another direction.
When the Twins drafted Stewart fourth overall, the allure of a $4.5 million signing bonus was too much to pass up. It was a major leap of faith for Minnesota's draft department, which had long had its sights set on the prized pitching talent. Much has been made of the fact that Hunter Greene, a teenage phenom out of California, could be the first prep right-hander to ever be selected with the first overall pick this June. There's a reason for that; such players bring a relatively higher level of risk and uncertainty.
But Stewart had all the requisites. A football player's build. A hard-moving fastball to go along with a potentially dominant slider. The prototypical bulldog demeanor on the mound. Ace upside.
What's To Like
Those aforementioned traits remain intact. Stewart has checked one very important box off the list by staying healthy and on the field. That is hardly a given for young kids who throw in mid-90s or above. Tyler Kolek, the fireballing righty selected second overall by the Marlins a year after Stewart's draft, just lost his entire 2016 campaign to Tommy John surgery. It's a major setback in a budding career.
Stewart has avoided such pitfalls and thus has progressed about exactly as one would hope. Since starting full-season ball in 2014 he has ascended to a new level each year, finishing last season as a 21-year-old in the Class-AA Southern League, where the average player was about three years his elder.
From year to year, the right-hander has increased his inning totals from 87 to 129 to 143, prepping his arm to be ready for 200 frames once he reaches the majors. You compare that to a guy like Jose De Leon, who at 24 still hasn't thrown even 120 innings in a season, and it's easy to see the value.
While reliably taking his rotation turns, Stewart has produced. He has a shiny 2.84 ERA as a pro and hasn't finished above 3.20 at any level. Opponents have struggled to square him up, with only 12 home runs in 1,600 plate appearances. Last year he made what many consider the toughest jump in the minors, but hardly looked overmatched in Double-A, picking up wins in nine of his 16 starts while posting a 3.03 ERA.
What's Left To Work On
In the entirety of his minor-league career, Stewart has struck out 15.4 percent of the batters he has faced, and walked 8.4 percent. I couldn't figure out an efficient way to do the definitive research, but I can say with confidence that there are very few, if any, successful starting pitchers in the majors who registered such low rates in both categories as prospects.
For a more manageable exercise, let's compare Stewart's established K and BB rates in the minors with those of each pitcher who made a start for the Twins last year.
Kohl Stewart: 15.4% K / 8.4% BB
Ervin Santana: 23.4% / 8.4% BB
Kyle Gibson: 21.7% K / 6.7% BB
Tyler Duffey: 20.2% K / 5.2% BB
Ricky Nolasco: 23.3% K / 7.0% BB
Tommy Milone: 22.7% K / 4.0% BB
Jose Berrios: 25.3% K / 7.6% BB
Pat Dean: 14.0% K / 4.8% BB
Hector Santiago: 24.3% K / 10.7% BB
Phil Hughes: 28.8% K / 6.4% BB
Andrew Albers: 18.4% K / 5.3% BB
Alex Meyer: 27.3% K / 10.0 % BB
So, on an historically poor starting unit, only three players had minor-league walk rates worse than Stewart has (Santana, Santiago, Meyer) and each made up for it with plenty of missed bats. The only one with a lesser K-rate in the minors was soft-tossing lefty Pat Dean, who balanced the heavy contact with pinpoint control.
Of course, this is an incomplete picture. Stewart is still a 22-year-old with, perhaps, multiple full minor-league seasons ahead of him yet. But up to this point he has logged 380 professional innings with a K/BB ratio below two. You just don't see effective big-league starters with that in their track record. The core tenet of pitching, in modern analysis, is that there are two things a guy can directly control, with no luck or external factors involved: how many he strikes out, and how many he walks. If you can't do either particularly well, it almost always ends up biting you.
Stewart will likely start the season in Chattanooga, where he must prove that his sterling ERA was more legit than his underwhelming peripherals. It's not unthinkable he could continue to plow through lineups with pedestrian strikeout and walk numbers, given that his sharp bending pitches always seem to to miss the sweet spot. Perhaps he earns another midseason promotion and reaches Triple-A. But as you climb the ladder, eventually inducing weak contact stops being enough on its own.
What he needs to do is start missing more bats. It isn't a huge stretch to believe he will. ESPN's prospect guru Keith Law suggested that Stewart could easily increase whiffs by leaning more heavily on his four-seamer and slider. The righty has mostly been a pitch-to-contact sinkerballer, and given the results it's hard to complain.
So what if this has all been part of some ingenious plan by the organization to preserve his arm, and Stewart is getting ready to unleash the true extent of his arsenal as he approaches the majors? It sounds far-fetched, and I'll believe it when I see it.
But the fact is this: many analysts – even those who emphasize statistics and recognize the red flag his K/BB ratio represents – still see Stewart as an eventual mid-rotation starter or better. Until someone actually starts hitting him, it's hard to disagree with that notion, in spite of the dubious underlying indicators.
Read up on our previous installments in the Twins Daily top prospects series:
TD Top Prospects: #20-16
TD Top Prospects: #15-11
TD Top Prospects: #10 Lewin Diaz
TD Top Prospects: #9 Travis Blankenhorn
- tarheeltwinsfan likes this