MASH Report (1/14/16) – Tommy John Surgery Extravaganza

I heard a recent podcast discussion on whether or not it is safe to draft Michael Pineda based on his Tommy John surgery chances in 2016. Pineda would definitely be considered a risk because of the month he spent on the DL with a forearm strain and the way his velocity oscillated around the time of the injury.


Coming into the 2016 season, I pegged his DL chances at 51%. Going on the DL for a couple of weeks or missing more than an entire season are two completely different outcomes. The following is a deep dive into Pineda’s and other pitchers’ Tommy John surgery chances.

To get the needed information, I used Jon Roegele’s Tommy John list and the disabled list information I collect every year (links to both). With the data, I used the last four seasons (2012-2015) when Tommy John surgeries (TJS) exploded (link).

Additionally, I only used data from the season before to help predict the future data. I am trying to find a pitcher’s TJS chances now, not once the season starts. Finally, I am only looking for pitchers who may have the surgery in the months that matter. Predicting a TJS in November is useless because we know the pitcher is out for the next season and there are no games going on. I will only look at TJS changes from February (when pitchers start to really stretch out) to September. To start with, here is a monthly TJS breakdown for the four years in question.

TJS by Month
Month Count Percentage
February 2 2%
March 17 16%
April 26 25%
May 17 16%
June 16 15%
July 14 13%
August 7 7%
September 5 5%

As the table shows, most of the operations occur before are early in the season. If an at-risk pitcher can get through the first couple of months healthy, their TJS chances drop quite a bit.

Now, here are the leagues TJS surgery chances for all pitchers given a minimum number of games or games started the previous season.

Overall TJS Chances
Minimum # of G or GS TJS rate Count
No minimum 3.5% 2695
10 or 5 4.1% 2100
20 or 10 4.4% 1699
30 or 15 4.4% 1437
40 or 20 4.7% 1198

I wouldn’t read too much in the numbers increasing as pitchers throw more. What I would take from that chart is about every pitcher has between a 4% and 5% chance of having TJS or about 2/3rd of a pitcher per team.

Moving on to Pineda, he has the extra baggage of having an arm issue the previous season. Here are the TJS chances if you know that the pitcher had a specific arm injury the previous season.

TJS Chances With Previous Arm Injury
Minimum # of G or GS TJS rate Count
10 or 5 (elbow) 14.4% 153
20 or 10 (elbow) 15.9% 107
40 or 20 (elbow) 25.5% 55
10 or 5 (shoulder) 2.7% 182
20 or 10 (shoulder) 2.8% 145
40 or 20 (shoulder) 1.3% 75
10 or 5 (other arm) 7.6% 79
20 or 10 (other arm) 6.0% 67
40 or 20 (other arm) 2.6% 38

There’s a four to five times increase in a pitcher’s TJS chances if they had a previous elbow injury, with the chances jumping to 25% for an established pitcher.

Now, moving onto the all-important factor, velocity. Last year, I looked at how harder throwers were more injury prone. Here is how velocity relates specifically to TJS chances.

TJS Chances by Fastball Velocity
Minimum # of G or GS TJS rate Count
40 or 20 (93 mph or more) 6.8% 381
20 or 10 (93 mph or more) 6.0% 535
10 or 5 (93 mph or more) 5.7% 637
40 or 20 (90 to 93 mph) 4.1% 537
20 or 10 (90 to 93 mph) 4.3% 740
10 or 5 (90 to 93 mph) 4.2% 915
40 or 20 (90 mph or less) 2.9% 280
20 or 10 (90 mph or less) 2.4% 424
10 or 5 (90 mph or less) 2.4% 548

While a ~2% increase in the chance of a TJS may not seem much, it goes a huge way in explaining the overall league-wide jump. The percentage of pitchers who threw over 93 mph in 2002 was 12% and now it is 32% of all pitchers. With a near tripling in hard throwers, no wonder TJS rates are way up.

Pineda probably has around a 6% chance of having TJS because of his reported forearm issue. His chances don’t get projected up since he throws under 93 mph. I would consider his TJS changes to be about 50% higher than the league average, but not to the point of not drafting him.

• Jennifer Langosch gives an update on a some rehabbing Cardinal players.

Randal Grichuk, who underwent a sports hernia surgery in December, has resumed physical activity without issue. The Cardinals also have received encouraging reports on reliever Jordan Walden, though the team is approaching his status a bit more cautiously given that he missed the final five months of the 2015 season with forearm and shoulder issues.

Molina’s timetable remains fluid, and he continues to wear a cast on his left thumb to protect it during the healing process. That cast is expected to come off later this month, at which time the medical team will get a better feel for how much strength Molina will need to regain.

While the Cardinals anticipate Molina being limited for much of Spring Training, Mozeliak has said the club is optimistic the veteran catcher will be behind the plate by Opening Day.

Hunter Harvey and Dylan Bundy reported they are completely healthy.

Right-handers Hunter Harvey and Dylan Bundy, the Orioles’ top two prospects, reported to the club’s annual minicamp on Monday with clean bills of health, a welcome development after a few injury-plagued seasons.

Players possibly on the DL in 2016

The Red players have had updates since the last report. Click on the “Date” for a link to go to the latest article on the player.

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 once, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.

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NL Rulesmember
6 years ago

Any news on Grichuk’s elbow woes from last season (speaking of TJS)? His back issues were cleared up by changing his workout routine. And his groin/sports hernia injury looks to be behind him.