Tony Gonsolin and Recent Tommy John Surgery Trends

Between Shohei Ohtani, Félix Bautista, and now Tony Gonsolin, the fragility of ulnar collateral ligaments has been an all-too-frequent topic of conversation within the past week. Gonsolin, in case you haven’t heard, is headed for Tommy John surgery on Friday, while we’re still waiting to hear whether the UCL injuries of Ohtani and Bautista are significant enough to merit going under the knife. Between that trio and the Rays’ Shane McClanahan going down earlier this month — and the fact that neither Gonsolin nor McClanahan are the first members of their teams’ rotations this year to need such surgery — it certainly feels as though we’re dealing with a lot of Tommy Johns lately, so it’s worth cutting through the numbers.

First, however, let’s spare a few paragraphs for Gonsolin and the Dodgers. The 29-year-old righty was coming off an All-Star season in which he posted a 2.14 ERA and 3.28 FIP in 130.1 innings, and owned similarly impressive career marks (2.51 ERA, 3.45 FIP) despite his intermittent availability due to injuries, which included a six-week absence near the end of last season due to a forearm strain, and just two appearances totaling 3.1 innings afterwards, one of them a four-out start in the 2022 Division Series. After spraining his left ankle during fielding drills in early March, he was playing catch-up and never seemed to find a comfort zone. He began the regular season on the injured list, finally debuting on April 26, and while his run prevention numbers looked good in the early going, his peripherals told another story, and his average fastball velocity was down. On June 11, manager Dave Roberts alluded to some health issues with Gonsolin, noting that his between-starts recovery “hasn’t been great,” and wondering if he was having trouble getting loose or pacing himself. In his next start two days later, Gonsolin threw six shutout innings but averaged just 91.1 mph with his four-seamer, two full ticks below last year.

To that point, Gonsolin had a 1.93 ERA but a 4.25 FIP, and soon he began to get roughed up on a routine basis. Over his next seven starts, he allowed four or more runs six times, producing a 7.25 ERA. Following a 3.1-inning, five-homer, 10-run stinker on August 18, Gonsolin’s second bad start out of three, Roberts told reporters that Gonsolin had been pitching through an unspecified “arm issue” for four to six weeks and would likely head to the injured list. On Sunday, the Dodgers acknowledged that surgery was an option, and on Monday it was revealed he’d undergo Tommy John on September 1.

Gonsolin had apparently been pitching through a UCL tear, something he and the Dodgers knew based on imaging done after that June 13 start. Mindful of the concurrent losses of Dustin May and Julio Urías to the IL, Gonsolin elected to pitch through the injury. “I was just hoping I could make it through the season, put up good numbers and just post,” he told reporters. “I thought I had full capability to do that.”

Gonsolin did have financial incentives to gut it out, and the Dodgers let him do so. Via the two-year, $6.65 million extension he signed in January, he earned one point for every start or relief appearance of at least 3.1 innings. For reaching 14 points, he added $500,000 to next year’s base salary of $3.4 million, with additional increases of $500,000 apiece for reaching 16, 18, 20, 24, and 28 points. That 3.1-inning shellacking got him to 20 points, meaning that he’ll make $5.4 million next season while rehabbing after surgery. He’ll have two years of club control remaining after that.

With May out due to his own Tommy John surgery — his second, alas — the loss of Gonsolin leaves the Dodgers with a rotation of Urías, Clayton Kershaw, Lance Lynn, and rookies Bobby Miller and Ryan Pepiot. Kershaw is still building his pitch count back up following a six-week absence due to shoulder soreness. Urías has not had his typically strong season, posting a 4.41 ERA and 4.43 FIP. Lynn has improved considerably since being acquired from the White Sox at the trade deadline, using a new pitch mix to post a 2.03 ERA in five starts for Los Angeles compared to a 6.47 mark for Chicago. Miller, the team’s top pitching prospect, has been dazzling at times but has also spiraled his way into big innings; he has a 4.00 ERA and 3.64 FIP. Pepiot has only pitched three times for the Dodgers this season after missing all of the first four and a half months due to an oblique strain; Wednesday night’s start against the Diamondbacks was his first major league start since last August 21. Deadline acquisition Ryan Yarbrough is a bulk alternative, while Gavin Stone and Emmet Sheehan are back at Triple-A Oklahoma City after taking their lumps for the Dodgers. Walker Buehler, who is rehabbing his way back from his second Tommy John surgery, has yet to throw more than an inning at a time at the Dodgers’ training complex, and isn’t likely to be built up to a starter workload by the time the playoffs roll around.

Unless Urías recovers his form, that doesn’t exactly look like the makings of an imposing postseason rotation. The even bigger question is what happens next year given that he, Kershaw, and Lynn are all poised for free agency, though the last of those pitchers has an $18 million option. The Dodgers should have Buehler back in working form, and certainly some of the young arms they’ve shown off as well, but they’ll need some veterans to stabilize the unit and at the very least eat innings. That Kershaw will end this season 40 or 50 strikeouts short of 3,000 could help incentivize his return to the fold, as he’d look very weird celebrating that career-capping milestone as a Texas Ranger (and haven’t the Rangers spent enough on pitching lately?).

All of those are problems for another day. As for the topic of UCL reconstruction, according to Jon Roegele’s Tommy John Surgery Database, Gonsolin will be the 22nd major league pitcher to undergo the procedure this year, a count that doesn’t include Ohtani or Bautista, whose courses of action have yet to be determined. Here’s how the numbers compare over the past decade and a half:

A caveat here: While the drop-off in professional pitchers undergoing the surgery this year looks encouraging, I wouldn’t take the current count as gospel; minor league injuries tend to be underreported in general, and often with delays involved. When I look back at past versions of this exercise, it’s clear some of the annual numbers have grown. The major league totals I’d regard as comprehensive, however — it’s tough to miss those.

Anyway, at the major league level, this year’s total of 22 TJs including Gonsolin is down from last year’s 26, though of course we could still see more before the end of the year. We’re still well below the single-season high of 35, set in 2012, and the spike to 31 in ’21, which likely owed something to pitchers ramping up after the pandemic-shortened season. The downward trend since 2021 is offset by the reality that the four-year average of 27 is the highest it’s been since 2012–15 (also 27), and it’s almost certainly destined to go higher; last year there were five TJs after September 1, while in 2021 there were four.

Having said that, I don’t see anything yet to suggest that the new pitch clock rule is leading to any kind of spike in TJs (there were a handful of articles in May and June exploring the question). It is notable that the severity of pitcher injuries — as in, longer stays on the IL, even after accounting for the increase in the minimum stint from 10 days to 15 — has risen over the past couple of seasons according to Baseball Prospectus’ Derek Rhoads and Rob Mains. “Compared to 2021, the increase in average IL stint for pitchers this year from the start of the season this year is 5.4 games through July 31 and 5.3 games through the 124th day.” (The 124th day this year was July 31, but the authors are just covering their bases to account for last year’s lockout). Additionally, Rhoads and Mains presented a graph showing that the share of pitcher ILs stay lasting 25 days or longer crossed the 50% threshold last year and that eyeballs somewhere in the mid-50s now. Still, it’s worth remembering that, as longtime big league athletic trainer turned analyst Stan Conte told MLB.com’s Anthony Castrovince, “[The injured list] is a roster management tool, not an injury database.” With TJs, we have some accounting to fall back upon.

The Dodgers aren’t the only team to lose two of their top starters to TJ this year. The Rays lost Jeffrey Springs in May, before losing McClanahan, and I’m not even counting Drew Rasmussen, who underwent the UCL internal brace procedure — which takes less time to return from but is far less common — in July. The Rockies lost both Germán Márquez and Antonio Senzatela, while three other teams have lost two major league pitchers to TJ this year, namely the Angels (José Quijada and Austin Warren), Reds (Connor Overton and Reiver Sanmartin), and Twins (José De León and Tyler Mahle). Fifteen teams haven’t lost anyone at the major league level this year, thankfully.

With Ohtani’s fate in the balance, with May and McClanahan both having undergone their second TJs, and with Buehler working his way back from his second, I did some research into their frequency as well. At the major league level, two other pitchers have gone back for seconds this year, namely Trevor Rosenthal, who hasn’t pitched in the majors since 2020 due to other injuries, and Jacob deGrom, who was just six starts into his $185-million contract when his elbow finally gave way.

As you might surmise from the pandemic-era wave of TJs, we’re seeing an increasing number of revisions at the major league level, though we’re still talking pretty small numbers. Here’s the same period from the graph above, broken into first-timers and second-timers (or, in the cases of Jason Isringhausen and Jonny Venters, third-timers):

Back in 2014, a massive group of 11 pitchers underwent a second (or in the case of Venters, third) TJ, and by and large, the outcomes were bleak. Four of them (Pedro Figueroa, Jeremy Hefner, Jarrod Parker, and Josh Johnson) never pitched another big league game, and three others barely made a dent: Brandon Beachy only made two more appearances but was still trying to come back as late as 2019, while Sean Burnett and Cory Luebke each made 10 or fewer additional major league appearances. Venters, Tyler Chatwood, Kris Medlen, and Peter Moylan were the success stories in that they each returned to pitch in multiple seasons, but their post-second TJ careers were limited in impact.

Return rates have improved since then, in that 13 of the 18 pitchers to undergo a second TJ in the 2015-20 span made it back to the majors, with Mike Clevinger (2020), Nathan Eovaldi (2016), and Jameson Taillon (2019) all sticking in rotations for multiple seasons. Eovaldi and Taillon both pitched well enough to net lucrative free agent deals, and Eovaldi has since made two All-Star teams. Another pitcher from that span, Caleb Ferguson, has emerged as a mainstay in the Dodgers’ bullpen.

One thing that separates that 2015-20 group from the Class of 2014 is longer timespans between surgeries. The 11 pitchers from 2014 averaged only 4.5 years between surgeries, with Beachy, Hefner, Luebke, and Venters each needing a follow-up within two years; only Burnett and Chatwood went more than seven years between. From the 2015-20 group, the average is up to 5.9 years, with only two pitchers needing a revision within two years (Tim Collins and Joel Hanrahan). Of the four from that group who went more than seven years between surgeries, two of them were Clevinger (8.3 years) and Eovaldi (9.2 years), but of the other two, Edinson Volquez (8.0 years) and Sam Freeman (10.2 years), the former made just 18 more appearances with ERAs above 6.00, while the latter never returned to the majors.

At this writing, I have not done the full math on before/after performance comparisons, or compared the surgery-to-return intervals of the successes to the rest, but sometime after 2014, teams realized that returns from second surgeries needed more time than the typical 13-15 months for first surgeries. To cherrypick a few data points, Clevinger (18 months to return to the majors), Eovaldi (21), Ferguson (20) and Taillon (20) reflect this adjustment in thinking, but then so did Volquez (20). Via a 2020 paper in the Orthopaedic Journal of Sports Medicine that synthesized the results of 29 previous studies that met their methodological standards, we do have some systematic accounting to go by:

After primary UCLR [ulnar collateral ligament reconstruction], Major League Baseball (MLB) pitchers returned to play in 80% to 97% of cases in approximately 12 months; however, return to the same level of play (RTSP) was less frequent and took longer, with 67% to 87% of MLB pitchers returning in about 15 months. RTP rates for MLB pitchers after revision UCLR were slightly lower, ranging from 77% to 85%, while RTSP rates ranged from 55% to 78%… All studies found a decrease in pitching workloads after UCLR. Fastball usage may also decrease after UCLR. Changes in earned run average and walks plus hits per inning pitched were inconclusive.

Based on Roegele’s data, no pitcher has returned from even a first Tommy John surgery in less than 13 months since the Cardinals’ Dakota Hudson, who did so in 362 days (from September 28, 2020 to September 4, 2021), which is why what Buehler and the Dodgers are doing with regards to his second surgery (which took place last August 22) feels incredibly risky. Hyun Jin Ryu returned from his second surgery in 13 1/2 months, but he also went a record 18 years between surgeries, and cashed in via an $80 million free agent contract signed in December 2019. Buehler is making $8.025 million in his penultimate year of club control, and thus putting a very large multiyear payday on the line by rushing back. For his sake, I’d rather see the Dodgers throw the brakes on his return, particularly given what we know about the impact of high velocities on UCLs.

As for more recent revision recipients, Ryu is one of just three pitchers (out of 14) who has undergone a second TJ since the start of 2021, and he has all of five starts under his belt, though he’s pitched quite well. Of the other two, Kirby Yates, who had his revision done in March 2021, is having a solid season in the Braves’ bullpen, while John Curtiss, who had his in September ’21, made just 15 major league appearances for the Mets before recently undergoing surgery to remove loose bodies from his already-scarred elbow.

Of the rest, there are a few hopeful stories. Chris Paddack, who had his second surgery on May 18, 2022, has a rehab assignment lined up to start on September 6, with hopes of returning later in the month. The Reds’ Tejay Antone — the name is a bit on the nose in this context — had his revision on August 27, 2021; he battled additional elbow troubles earlier in the season but has made 14 minor league rehab appearances, the most recent one on Wednesday with Triple-A Louisville. Hopefully he could return in September as well. Joe Ross, who had his revision in June 2022, has made three minor league appearances for the Giants in the past 10 days, while Brandon Bailey, who had his second TJ in February ’21, has two minor league appearances in the White Sox organization this month in his first game action since ’20. John Axford, who went nearly 18 full years between his first and second surgeries, pitched for Team Canada in the World Baseball Classic, but while the 40-year-old righty has not officially retired, he is unsigned.

If Ohtani plays out the rest of the season before undergoing his second TJ (assuming his tear is severe enough to merit it, which is an unknown) in October, presumably he won’t pitch at all until 2025. That would give him at least 18 months between surgery and return, and given the dollars — and velocity — at stake, it wouldn’t be a surprise if he waited longer.

Because of the stresses that repeated high-intensity throwing places on arms, Tommy John surgeries are an inevitability within baseball. Within the data, we’ve at least begun to see signs of teams learning not to rush TJ recipients back to the majors. That’s small progress, but it is something to hang onto, at least.