Harrison has had thoracic outlet syndrome twice–once in each shoulder. Interestingly, he had the first surgery on his throwing shoulder in 2009 and was able to return and pitch effectively for a few years. He had a rough year (63 1/3 innings) in 2009 pre-surgery and struggled throughout 2010 as well. While his fastball velocity wasn’t particularly low during these two seasons, it did increase a couple ticks as he became further removed from surgery, eventually peaking at 93.9 MPH in 2011.
Harrison also improved his command as he became further removed from his surgery. His strikeout and walk rates were significantly better in 2011, and he gave up considerably less hard contact (including fewer home runs) that year.
Harrison appears to be the exception on this list, as his best seasons came after his thoracic outlet surgery. His age was certainly a factor, as he was just 24 at the time of his injury. Even so, it took him a season and a half to recover fully and pitch effectively for the Rangers, and this success only lasted two years, before Harrison went down with another series of injuries.
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There are certainly other pitchers not included in this article who dealt with thoracic outlet syndrome before the PITCHf/x era. In addition, there are pitchers like Noah Lowry, who never threw a major league pitch after thoracic outlet surgery, despite only being in his late 20s at the time. While there may not be enough data to say anything definitive about pitchers recovering from this injury, there are a few possible trends worth noting.
The injury has the potential to seriously hurt a pitcher’s velocity, although this hasn’t been the case in all situations. While pitchers like Chris Carpenter and Shaun Marcum saw a noticeable drop in their velocity, Matt Harrison saw his velocity increase as he became further removed from the surgery.
The biggest area these pitchers seemed to struggle was with their command, both in and out of the strike zone. This manifested itself in slightly higher walk rates, a lower percentage of pitches in the strike zone, and hard contact on pitchers that were in the strike zone, including abnormally high home run rates.
There aren’t a lot of pitchers who have had this injury, but the track record isn’t good. Counting on a pitcher who has been through this injury is a terrifying proposition, especially considering the fact that the pitchers in this article are some of the most injury-prone players in recent memory. Perhaps Jaime Garcia can break the trend and give hope to pitchers who suffer this injury in the future. His success in seven starts this year defies some of the trends shown by the other pitchers with this injury. Still, until we have a better track record of pitchers returning from thoracic outlet syndrome, it will keep its reputation as one of the worst arm injuries that a pitcher could suffer.
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Nick Lampe is a contributor at Beyond the Box Score and Viva el Birdos. You can follow him on Twitter at @NickLampe1.