Michael Kopech and the Cold Comfort of Tommy John Trends

Just 14.1 innings: that’s all we’ll get from Michael Kopech at the big-league level until 2020. On Friday afternoon, the White Sox announced that the 22-year-old fireballer has a significant tear in his ulnar collateral ligament and will require Tommy John surgery. Unlike the previous gut punch that baseball fans were dealt just two days earlier — that Shohei Ohtani needs the surgery, as well — there was no dramatic buildup, no injection of platelet-rich plasma after the first report of a UCL sprain, followed by rest and hope backed with worry that it wouldn’t be enough to stave off surgery. On Wednesday, Kopech was pitching. On Friday, he was cooked, though he’ll go about getting a second opinion before the fork, and ultimately the knife, are stuck in him.

Granted, there were signs on Wednesday: Kopech exhibited diminished velocity even before sitting through a 28-minute rain delay. When play resumed, he surrendered three homers and six runs to the Tigers while retiring just one hitter in the fourth inning. The guy who, two years ago while still in the Red Sox organization, was reportedly clocked at 105 mph threw just one first-inning fastball that topped 95, according to the data at Brooks Baseball. His average four-seam fastball velocity for the first inning declined for the third time in a row — in a major-league career that’s four outings long:

Kopech’s Declining Fastball Velocity
Date Opponent 1st Inning Overall
August 21 Twins 97.1 97.1
August 26 Tigers 96.3 95.7
August 31 Red Sox 95.3 95.8
September 5 Tigers 94.0 94.2
SOURCE: Brooks Baseball

Oddly enough, rain affected Kopech’s first and third starts, as well, also in Chicago. His debut ended after two rain-shortened innings and his August 31 start ended after three. He didn’t allow a run in either outing and conceded just one in six innings in his lone road start, in Detroit, on August 26. His tally entering the fateful start was thus one run allowed in 11 innings, with 11 hits, nine strikeouts and one walk, an extension of the second-half strike zone-pounding roll that carried him to the majors in the first place. Because he has learned to dial back his velocity in order to improve his control, he didn’t crack 99 mph on any pitch, let alone 100.

Kopech didn’t sound any alarms about his elbow in Wednesday’s postgame interview, telling reporters, “I missed a lot of spots and got taken advantage of, which is going to happen when I’m not throwing the way I need to. I was pitching like I was throwing 100 [mph], and I was throwing 93-94.”

After the news of his diagnosis, however, Kopech was reported to have experienced trouble getting loose during warmups, believing that he was simply dealing with stiffness:

“If you’re looking for a specific pitch or date, I couldn’t tell you,” Kopech said. “It’s been gradual.”

“I thought it was just a little discomfort. I thought it was something I could throw through,” he said… “[I wanted] to see if there was something I could fix. This isn’t the answer I expected.”

“There were no inklings whatsoever,” said general manager Rick Hahn while delivering the bad news. “Nothing that he reported, nothing in the injury reports, nothing with his delivery, nothing with any of the analytics of his mechanics, nothing until yesterday, when he rightfully shared with us that he didn’t feel quite right getting loose during that start against Detroit.”

It’s been a particularly rough year for the UCLs of top prospects. Going back to the FanGraphs’ top-100 list from February, we’ve lost not only Kopech (No. 20 on that list) and Ohtani (No. 1) but also the Rays’ Brent Honeywell (No. 15), the A’s A.J. Puk (No. 30), and the Reds’ Hunter Greene (No. 42). Per Baseball America’s list, those five were all in the top 30. Depending upon which of those lists you’re consulting, that’s five of the top-18 (FG) or -14 (BA) pitching prospects felled, counting the two-way players (Ohtani, Greene, and the Rays’ as-yet-unharmed Brendan McKay) as pitchers because that’s where the risk is. Whether their UCLs are actually more vulnerable due to double duty is a question for another day.

The more important question from an industry-wide perspective is the extent to which the UCL tears of this cohort of blue-chippers and so many others are connected to the game’s trend towards increasing velocity. (According to Pitch Info’s data, this year’s average four-seam fastball speed of 93.3 mph is down 0.3 mph from the previous year but still 1.1 mph higher than in 2009.) In a 2015 study by Julien Assouline published on the FanGraphs Community blog, Assouline used PITCHf/x data dating back to 2007 and Baseball Info Solutions data dating back to 2002. He found higher rates of Tommy John surgery among major-league pitchers in the 92-95 mph bucket (~27% for both sources) than the 89-92 bucket (20-21%) — and higher still in the 95-plus bucket (31-35%). The trend was generally applicable both to relievers and starters, though regarding the latter group, he found some ambiguities when using BIS data, which had a larger sample size.

Meanwhile, a study conducted by the Department of Orthopaedic Surgery at Henry Ford Hospital, published in the April 2016 Journal of Shoulder and Elbow Surgery (abstract here via PDF), found a connection between higher fastball rates but not necessarily higher velocity. The study, which covered 83 pitchers who had endured the surgery over an eight-year period (a smaller sample than Assouline’s study) and compared them to a control group matched for age, position (starter/reliever), size, innings pitched, and experience, found no differences in pre-surgery pitch velocities for fastballs, curveballs, sliders, or changeups. However, research also revealed that the pitchers who received Tommy John surgery threw significantly more fastballs than the control group, with a 2% increase in risk for UCL injury for every 1% increase in fastballs thrown, and that fastball usage above 48% was “a significant predictor of UCL injury.”

For what it’s worth, the small sample of Kopech’s Pitch Info data for his four starts shows him throwing four-seam fastballs 62.5% of the time. For Ohtani’s 10 starts, he threw four-seam fastballs 46.3% of the time and split-fingered fastballs — which went unmentioned in the study, as did cut fastballs and any distinction between two- and four-seamers — 22.4% of the time (sinkers just 0.1%). For what scant data we have from Honeywell (the 2016 Arizona Fall League and the 2017 Futures Game) and Puk (that Futures Game and one 2017 spring-training outing) via Brooks Baseball, the aggregated rates of fastball usage are well above 50%, but the sample sizes and relief-length outings make it unwise to draw conclusions.

Dr. Glenn Fleisig, the research director at the American Sports Medicine Institute (which was founded by Dr. James Andrews, the renowned orthopedic surgeon), noted at the time of the study’s publication that it did not account for mechanics or other factors, telling USA Today’s Mike Vorkunov, “Previous works by me and others have shown two fastballs of the same speed with poor mechanics are more stressful than good mechanics. I think this study by itself is a small part of the puzzle. You also have to look at the pitchers’ mechanics — which is the purpose of the pitching coaches and biomechanists. So not all fastballs are the same.”

Two years removed from the Ford study, the league-wide rates of four-seam fastball usage are virtually unchanged (37.2% in 2016, 37.4% this year, with a dip to 36.7% last year), but the overall trend is downward when including splitters (which have dropped from 18.7% in 2016 to 17.0% this year) and cutters (down from 6.7% to 5.6%) as fastballs:

While most teams probably took note of the study, it’s likely that the minute changes above have little to nothing to do with that, at least at the upper reaches. As Vorkunov wrote at the time, “[U]sing this study to change pitching habits at the major league level seems to be a non-starter for [the Mets] or for any team. Especially if the results don’t create a blinking red light that shows a danger.” Perhaps at the amateur levels, or the entry levels of professional baseball, there has been change, but it’s not measurable via this data.

At the very least, the frequency of Tommy John surgery among major-league pitchers has remained more or less unchanged in recent years. Whenever Kopech and Ohtani (who’s hitting so well that he may finish out the season as a DH) undergo TJS, they will run the total of major-league pitchers having the surgery this year to 19, one more than last year and the same total as in 2016. That said, there could still be some postseason surgeries to come, and the same is true for minor-league pitchers — recent history tells us to expect something on the order of another dozen from September 1 onward — but the trend may be moving in the right direction, past peak Tommy John.

Note that, as in my previous explorations of this topic, I’ve excluded all hurlers whose last presurgical levels were classified as high school or college because of the discrepancies in surgical timing, and I’ve excluded position players as well. Note also that since I last checked in, the total tally of surgeries for 2017 has increased to the point of equaling 2016; it appears that an additional 18 surgeries from 2017, all from various levels of the minors, where injury reporting is far from comprehensive, were entered into the database over the past six months. Thus it’s too early to pop the champagne corks to celebrate the trend abating.

At least it appears that it’s not getting markedly worse. At the moment, however, that’s cold comfort. When we’re losing full years of the very brightest prospects and young talents in the game, the Kopechs and the Ohtanis and the Greenes, it’s a damn shame, and a problem whose solution remains painfully and depressingly elusive.

Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011, and a Hall of Fame voter since 2021. Follow him on Twitter @jay_jaffe... and BlueSky @jayjaffe.bsky.social.

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5 years ago


5 years ago
Reply to  cperd

Between this and the Bears last night…just shoot me.

Shirtless George Brett
5 years ago
Reply to  MikeS

I’m a Royals/Bills fan. I’ll shoot you if you shoot me.

5 years ago

2015 wasn’t that long ago, buddy.