Last week, the bell tolled for the 2018 season of the Diamondbacks’ Taijuan Walker. The week before that, it tolled for the Padres’ Dinelson Lamet, and before him, the Angels’ JC Ramirez and the A’s A.J. Puk. If it feels like March and April are particularly full of Tommy John surgery casualties, that’s because they are, at least when it comes to recent history. In early March, just after Rays righty Jose De Leon discovered that he had torn his ulnar collateral ligament, I noted some recent trends regarding everyone’s favorite (?) reconstructive elbow procedure, including the extent to which those early-season injuries are rather predictive of the season-long trend. With April now in the books, and with my nose still in Jon Roegele’s Tommy John Surgery Database, the situation is worth a closer look.

Via the data I published in the De Leon piece, just under 28% of all Tommy John surgeries done on major- or minor-league pitchers (not position players) from 2014-17 took place in March or April, with the figure varying only from 24.8 % to 30.0% in that span. Even expanding the scope to include February as well, which doesn’t increase the total number of surgeries by much but does capture significant ones such as that of Alex Reyes last year — gut punches that run counter to the optimism that reigns when pitchers and catchers report — the range is narrow, with 27.5% to 33.0% of pitcher surgeries taking place in that span.

After my piece was published, a reader pointed out that The Ringer’s Ben Lindbergh took an in-depth look at the phenomenon, but intuitively, it’s not hard to understand. Not only do pitchers’ activity levels ramp up dramatically once spring training begins, as they move from lighter offseason throwing programs to facing major-league hitters and therefore place far more stress on their arms, but many pitchers are finally forced to reckon with injuries that did not heal over the winter.

Via Roegele’s data, 23 major- and minor-league pitchers underwent surgery in February, March, or April this year, a figure that falls between the 2016 and -17 totals:

Early-Season Trends in Tommy John Surgery Year Total Feb-Apr Feb-Apr Pct 2010 51 11 21.6% 2011 46 5 10.9% 2012 73 17 23.3% 2013 65 11 16.9% 2014 100 33 33.0% 2015 109 30 27.5% 2016 79 24 30.4% 2017 69 21 30.4% 2018 25 23 92.0% SOURCE: Tommy John Surgery Database Totals are for minor-league and major-league pitchers only.

Note that the early-season trend doesn’t hold up so well if you look back further than 2014, though the overall 28.4% rate for the 2010-18 period — a number that will go down as more pitchers fall victim this year — is still within the observed range. The breakdown of the pattern for years prior could simply be a data collection issue; Roegele began building his database in November 2012, and as his efforts have become publicized within the industry, there are now more eyes on every TJ surgery and (presumably) fewer going unreported below the major-league level. There are also fewer recorded as having taken place on January 1, Roegele’s shorthand for dates unknown within that calendar year; from 2010-13, it’s about 13%, falling to below 10% since the start of 2014.

Anyway, if recent form holds, based on the aforementioned range for the 2014-17 period, we can expect somewhere between 69 and 84 pitcher TJs this year, still well below the 100-plus in 2014 and 2015 but possibly a bit higher than last year. Re-running my graph from the De Leon article:

One other area of interest, particularly with the return of Jonny Venters fresh in mind: we’ve been seeing fewer revision surgeries — second (or even third) TJs — in recent years. As with first TJs, the revisions tend to be clustered in the spring period, though the sample sizes are small enough that there’s no predictive relationship to the year as a whole. For the second year in a row, the February-April window produced just one revision surgery:

Recent Tommy John Revision Trends Year Total Feb-Apr 2010 3 1 2011 3 0 2012 8 3 2013 6 0 2014 12 7 2015 9 3 2016 8 4 2017 6 1 2018 1 1 SOURCE: Tommy John Surgery Database Minor- and major-league pitchers only.

For the period, 35.7% of all TJ revision surgeries took place from February through April. I note the declining trend of revisions mainly as another possible sign that the industry is past what Travis Sawchik recently called “Peak Tommy John.”

Alas, that’s cold comfort to the poor pitcher who needed it in March, namely Jacob Lindgren. A 2014 second-round pick out of Mississippi State by the Yankees, the left-handed Lindgren made seven relief appearances for New York in May and June of 2015 before undergoing surgery to remove a bone spur. Due to a slow recovery, he never made it back to action that year, and he made just six appearances at High A Tampa in 2016 before undergoing his first TJ in August of that year. The Yankees non-tendered him that winter with the intention of re-signing him, but Braves GM John Coppolella swooped in and signed him to a major-league deal — even knowing that he would not pitch in 2017 — which apparently infuriated the Yankees. After throwing live batting practice in early March, he began experiencing elbow soreness, which ultimately led to a trip to Dr. James Andrews’ operating table.

So which teams have been hurt the worst this year by Tommy John surgery? Looking back at our Depth Charts projections, I’ve tried to estimate the losses. For seven teams, the toll is at least a full win:

On an individual basis, the injury to Seager — whose UCL tear was revealed on Monday — is by far the most impactful one in this class, but then again, he had the majors’ fifth-highest WAR in 2016-17. The team whose dust his Dodgers are eating, the Diamondbacks, have suffered the next-biggest blow by losing Walker, and four other teams have lost at least two wins worth. Of course, each of those teams may get some of that value back via the players who replace them — this is hardly a perfect accounting system — but it does help put the Seager injury, the rare one of a position player (I found just one major-league infielder who underwent the surgery in the past eight years) in perspective.