What to expect from Luis Severino’s rehab assignment

The road back to The Show begins tomorrow for Yankees pitcher Luis Severino, as the young ace will start his rehab assignment with the Low-A Tampa Tarpons. The two-time All-Star and 2017 Cy Young Award finalist missed the entirety of the 2020 season and the first third of 2021 after having Tommy John surgery to repair a partially torn UCL on February 27th, 2020, and the Yankees hope that his return will bolster a rotation that has simultaneously propped up a struggling offense and been beset by underperformance and injuries.

Despite improvements made in medical practices and technology in recent years, UCL repairs are tricky, and many attempts to return to play don’t go smoothly. With that in mind, what should Yankees fans expect to see in the coming month?

Let’s start with the scientific data. Last December, a team of scientists — Stephen J. Thomas, Ryan W. Paul, Adam B. Rosen, Sam J. Wilkins, Joseph Scheidt, John D. Kellyand Ryan L. Crotin — published a study titled, “Return-to-Play and Competitive Outcomes After Ulnar Collateral Ligament Reconstruction Among Baseball Players: A Systematic Review.” The study is an attempt to analyze not only how long Major League Baseball players take to return from Tommy John surgery, but how long it takes for them to return to their previous level of performance. Incorporating data from 29 previous studies, this team found that, following surgery,

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.

Right off the bat, it seems that the Yankees are at least aware of this trend, as Severino will not be returning to the mound in a game setting until a full fifteen months after the surgery, and will not return to a Major League mound until sixteen months have passed assuming everything goes well. The previous starting pitcher in the organization to undergo the surgery, Jordan Montgomery, likewise did not return to big leagues until fifteen months after his surgery — and since that was in the final week of September, he did not make a significant return until the following spring training. On top of that, since the following spring was the delayed 2020 season, he did not return as a full member of the rotation in the regular season until two years had passed.

How has this played out on a day-to-day basis? Let’s take a look at a few starting pitchers who have undergone Tommy John surgery in the last seven years. (The length of the rehab, along with the shortened 2020 season altering timelines, has resulted in me having to go back further than I would have liked for examples.)

The best-case scenario is most-closely represented in recent years by Yu Darvish. Having undergone surgery on March 17, 2015, the then-Rangers ace began his rehab assignment on May 1, 2016, (a little less than fourteen months later) throwing 32 pitches over two innings for Texas’s Double-A affiliate. After coming through the outing clean, he went on to make four more starts, increasing his workload by one inning in each outing. Following his final tune-up on May 22nd, in which he threw six scoreless innings, Darvish returned to the big leagues on May 28th with five one-run innings against the Pittsburgh Pirates.

Another relatively smooth recovery belongs to former Yankees pitcher Brandon McCarthy, who had Tommy John surgery as a member of the Los Angeles Dodgers on April 30, 2015. At first glance, McCarthy’s timeline seems to have been pretty much best-case scenario: having made his first rehab start on June 11, 2016, he returned to the Dodgers’ rotation on July 3rd after only four starts in the minor leagues, bringing him back to The Show only fourteen months after surgery. However, although it did not delay his return, McCarthy did have to be shut down temporarily due to “arm-related discomfort” following a live bullpen session as part of his throwing program. Even a smooth recovery has some bumps along the way.

Apologies to our crosstown brethren, but the worst-case scenarios both belong to members of the New York Mets. Despite the organization implementing an extended rehab plan for Zack Wheeler after undergoing surgery on May 25, 2015, which would bring him back just before the All-Star break in 2016, a series of setbacks — including an additional surgery to remove an undissolved stitch in his elbow and platelet-rich plasma injections to treat a strained flexor tendon — kept Wheeler off the mound for two full seasons.

More recently, Noah Syndergaard, who underwent surgery on March 26, 2020, was removed from his second rehab on May 25th this year and shut down for six weeks due to elbow inflammation. At the moment, despite originally having a mid-June return date (earlier than either Luis Severino or Chris Sale, who had Tommy John surgery before him), the Mets are not even sure if Syndergaard will pitch for them at all this year.

Which path will Severino will take back to the Bronx? Only time will tell. As the homegrown ace begins on this journey, it is important to remember that, no matter how successfully players have returned from this injury in recent years, it’s still an injury and still involved surgery — the rehab and recovery very rarely goes smoothly, and just making it back at all is a major accomplishment.