Pitcher Results After 2nd Tommy John Surgery
With Jacob deGrom and Walker Buehler coming back from their second Tommy John surgery (TJS), I wanted to go back and look at how pitchers performed after going under the knife a second time. While I had high hopes this study would find some useful adjustments, the results were mixed and probably point to the pitcher being more of the same.
I started out with the list of guys who had two Tommy John surgeries in Jon Roegele’s database. Then using weighted innings, I found the difference between several stats over certain time frames.
Timeframes
- y1: Season before the 2nd surgery.
- y2: Season of the 2nd surgery.
- y3: Season returning from the 2nd surgery.
- y4: Season after returning from the 2nd surgery.
In all, 45 pitchers had a second operation, and here are their season-to-season changes with the average age at the operation being 29 years old. One other factor is that xFIP and fastball velocity (FBv) weren’t always available, so the count on them is a bit lower.
Note: I would have liked to subdivide this group up by years between operations, but the sample size is already too small.
| Seasons | Matched IP | K/9 | BB/9 | ERA | WHIP | ERA | xFIP | FBv (fastball velo) | Count | Count for xFIP and FBv) |
|---|---|---|---|---|---|---|---|---|---|---|
| y1 to y2 | 1155 | 0.4 | 0.2 | 0.39 | -0.01 | 0.39 | 0.11 | -0.15 | 27 | 25 |
| y2 to y3 | 1142 | 0.9 | 0.1 | 0.20 | 0.12 | 0.20 | -0.04 | -0.31 | 26 | 24 |
| y3 to y4 | 1139 | -0.1 | 0.7 | 0.88 | 0.17 | 0.88 | 0.25 | 0.44 | 28 | 26 |
What a mess, nothing makes sense… at all. ERA constantly increases while xFIP stays constant. Walks and strikeouts both trended upward. Fastball velocity up from season 3 to season 4 but strikeouts even. And yes, triple checked my numbers.
For me, the simple conclusion is that there is no observable trend. Here is one more test, from the year before the surgery to the season after.
| Seasons | Matched IP | K/9 | BB/9 | ERA | WHIP | ERA | xFIP | FBv (fastball velo) | Count | Count for xFIP and FBv) |
|---|---|---|---|---|---|---|---|---|---|---|
| y1 to y4 | 1268.314724 | 0.58 | 0.48 | 0.25 | 0.03 | 0.25 | 0.07 | 0.1 | 24 | 20 |
The pitchers got a little worse over the full time frame but some loss should be expected with the average age being near 30.
Overall, pitchers seem to return from their second Tommy John surgery and throw comparable to when they did before the operation.
Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.
It is good information to know Jeff. My draft sheet comment about Nate Eovaldi having 2 TJ surgeries was not needed based upon this data. I love these statistical studies you do.
Yes very interesting. It means we should not lower expectations on pitchers coming off the 2nd TJ. I would have thought the opposite but the numbers don’t lie.
It might reduce noise if you used league adjusted stats (eg ERA-, xFIP-, etc) to account for run scoring environment when comparing separate seasons.
The FBv increase from Year 3 to 4 is interesting. Less noise in that one so I’d probably pay attention to that in the future.
Yes that’s interesting particularly with avg age being 29. So at that point the average age is 33.
The statistical sample is still too small to be accurate. And I’m not so sure the statistical divisions here are the most relevant. And all post 2 UCL reconstruction patients are not the same. Just some things to consider: 1- The % of pitchers that return to play at the highest level; it is not the same for multiple as for single reconstructive operations or for brace repair and then full reconstruction. The list of failures is not included. 2- Further, for those that do return to MLB levels, the risk for reinjury is higher; that’s logical given soft tissue scarring and bone alterations. Clevinger and Eovaldi, more recent “SP success” stories are proof, providing fewer innings, and persistent arm or shoulder girdle issues. This is logical and every orthopedist knows this and so advises their patients. 2- The players’ ages and mileage on those arms before 2nd TJ. Most TJ are done in the late teens- early 20’s, and the few with second operations mostly in their mid later 20’s, not their 30’s. A major risk factor for UCL tears is FB velocity. SP like deGrom, with 1400 IP, 99 MPH FB, and age 36 or 37 expected return, have multiple unfavorable dynamics at work; 3- Performance- For higher end SP, it really isn’t the same. Examples- Mike Clevinger 2.96 pre [2017-19], 4.03 since [2022-23]; Jameson Taillon 3.20 ERA pre [2018]; 4.33 since [ 2021-23]. Josh Johnson 3.09 pre [2006-10] and 4.52 post [2012-13, then quit needing 3rd surgery]. Only Eovaldi, who had 2nd TJ early at age 26, had 4.10 pre, with a 3.98 post has maintained or even bettered the same level of performance. 3- Concomitant surgery eg ulnar transposition also has its complications. While techniques have improved over time as has rehab, IMO, the jury is still out. While major league teams are stuck with contracts and these players, and hope for the best, fantasy managers should not leap to do so.
Thanks for sharing this info. Can you explain or link “weighted innings” and “matched IP”. I don’t know what those are.
Good information. Thanks Jeff
Ratios of 45 pitchers don’t tell you the whole story you need to know, This conclusion: “Overall, pitchers seem to return from their second Tommy John surgery and throw comparable to when they did before the operation” is not justifiable without comparing the average innings before and after surgeries.
Can you provide a list of pitchers? It would be interesting to see who didn’t come back, how many innings those who did were able to pitch upon returning. How many innings did they pitch prior to surgery?
1150 innings spread among 45 pitchers is 25 2/3. Under 26 innings per pitcher per year doesn’t show that pitchers came back and threw like they did before.
He linked to the database he used.
Agree. The conclusion not only doesn’t follow the data [ERA, WHIP rise], but then the discrepancy is assumed to be due to age alone without data proof. The reality is that a conclusion can’t be drawn, but rather seems forced. Variable contexts including age, degree of arthritis, other eg shoulder problems, if any, baseline innings and baseline absolute FB velocity pre surgery are not addressed, let alone change in innings, teams, park, league environment, or usage. As interesting as this topic is, the study design can’t answer the real question, and the number of participants [26] is way too small. The true answer will become apparent over the next few years. The orthopedic literature is less sanguine starting from the fact that there is a 10-15% decrease in return to play to 75%, which also took longer [21 months], and had impacts on subsequent innings [avg post years 3 years], workloads [less] and fastball usage post. For fantasy purposes, 99% of the list is irrelevant. For those of draftable interest, Clevinger, Taillon, Eovaldi, Capuano, Johnson, only Eovaldi has maintained his level, but hardly wo a bumpy ride or recurrent injury. Another current returnee H-J Ryu is the only one close to deGrom’s age, but very different arsenal. ERA pre 3.15 [2017-2021] and 3.45 post in return July 2023, but averaged < 5/start. The next few years with deGrom, Buehler, May, Paddack, will be instructive. But, going back to your comment, yes, the data above do not answer the question, and the conclusion is premature, if not incorrect.
Great stuff Jeff. I like how you publish these findings even if there is no interesting conclusion. Knowing these results is still a useful exercise.
That said, from a fantasy standpoint, my concern rostering a pitcher who has undergone two TJS hasn’t necessarily been how well he’ll pitch, but whether his next elbow issue will end his career.
Considering only two players (Isringhausen and Venters) have returned to the majors to pitch after a 3rd TJS, the sample used in this exercise captures only a partial look at the broader risks involved in rostering 2xTJ guys. Perhaps the number of pitchers who have retired instead of undergoing a 3rd procedure is impossible to find out. But it’s definitely a non-zero number.
I really enjoy how short and to the point this article is. I would love to see more posts like this that are just quick and dirty analysis of a specific situation. Thanks Jeff!