Philadelphia Phillies right-handed pitcher Zack Wheeler will officially miss the rest of the season with venous thoracic outlet syndrome (TOS), the team announced Saturday. Venous TOS occurs when at least one vein under the collarbone is compressed and damaged, according to Mayo Clinic.
Wheeler has been recommended to undergo thoracic outlet decompression surgery, which generally has a 6-8 month recovery timeline, per the Phillies’ release.
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The NL Cy Young candidate landed on the injured list last weekend. On Monday, he had a successful thrombolysis procedure to remove a blood clot near his right shoulder.
He then had a follow-up evaluation and received second opinions this week, according to the team.
Wheeler initially reported discomfort after an Aug. 15 start, a five-inning outing against the Washington Nationals. After feeling an abnormal heaviness in his shoulder, he received evaluations the following day. That’s when his blood clot, officially in his “right upper extremity,” was discovered.
While not often, major-league pitchers have dealt with this kind of issue before.
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Current Texas Rangers pitcher Merrill Kelly had surgery for venous TOS in August 2020 to remove a blood clot in his shoulder. At the time, he was with the Arizona Diamondbacks. While Kelly missed the rest of that season, he came back in 2021 and made 27 starts. The year after that, he made 33 starts and registered a 3.37 ERA. He’s now seven years into his MLB career.
There are different types of TOS. Another is neurogenic TOS, and it significantly affected the career of former Nationals ace Stephen Strasburg. Neurogenic TOS is actually the more common type, according to Mayo Clinic, which describes it as a compression of a group of nerves from the spinal cord that control muscle movements and feeling in the shoulder, arm and hand, potentially leading to numbness and tingling.
In 2023, Jesse Dougherty of The Washington Post wrote a story that illustrated the differences between Kelly and Strasburg’s injuries. He spoke to Robert Thompson, founder of the Center for Thoracic Outlet Syndrome at Washington University in St. Louis.
“They get lumped together, but venous TOS is typically clinically more acute,” Thompson told the Post at the time. “It presents suddenly without any preexisting symptoms. These are players who are playing normally — no pain, numbness, tingling, no nerve-type symptoms. And they suddenly get arm swelling, and there ends up being a clot in the subclavian vein.
“Neurogenic TOS is kind of a contrast because those patients typically do have somewhat long-standing symptoms, involving at least numbness and tingling, and they may have overt pain or more of an ache or fatigue. They may describe dead arm when they are throwing, particularly pitchers. And to some degree, those symptoms may have been going on a long, long time, and they’ve made compensatory changes in their posture and mechanics that may ultimately be hard to reverse. So they kind of come with a little bit more baggage.”
The sample size isn’t large for major-league pitchers and TOS, but Wheeler appears to be dealing with the more rare type of TOS, but with a less complex recovery process.
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How Wheeler responds to that recovery process is yet to be seen.
As of Saturday afternoon, the Phillies are leading the NL East, six games up on the second-place New York Mets, Wheeler’s former team. Wheeler is in his sixth season with the Phillies, with whom he’s made three All-Star teams and earned a Gold Glove Award.
Fortunately for Philadelphia, it has a deep starting rotation that helped pull off a sweep of the Seattle Mariners in historic fashion this week.
