Phillies’ Ace Zack Wheeler Diagnosed With Venous Thoracic Outlet Syndrome, Season-Ending Surgery Recommended

Philadelphia, PA - On August 23, 2025, the Philadelphia Phillies shared that their right-handed ace, Zack Wheeler, has venous thoracic outlet syndrome (VTOS). He is set to have surgery, which will end his season in 2025.

On Saturday afternoon, the team stated that after a successful thrombolysis on August 18 to remove a blood clot near his right shoulder, additional tests revealed subclavian vein compression linked to VTOS. The Phillies’ medical staff recommends first-rib resection and scalenectomy in the coming weeks. Recovery from the surgery is expected to take approximately six to eight months.

Dr. Michael Lieb, a vascular surgeon with no ties to the Phillies, shared that VTOS occurs when the subclavian vein is pressed as it exits the thoracic outlet. This can cause the arm to swell, change color, and feel heavy. ““After this procedure, patients are often put on blood thinners for a few months. They are also advised to avoid repetitive arm activities,” he noted.

Phillies President of Baseball Operations, Dave Dombrowski, affirmed the team’s trust in Wheeler’s long-term outlook. ““We expect him to return in six to eight months and be the Zack Wheeler we know,” Dombrowski said, citing assurances from specialists. Head Athletic Trainer Paul Buchheit said that Wheeler is “doing well.” He is also optimistic about Wheeler’s rehab timeline.

Before his injury, Wheeler had a 2.71 ERA. He led the Major Leagues with 195 strikeouts in 149⅔ innings. This made him a top contender for the National League Cy Young Award. Now that the season is over, the Phillies will rely on their pitching depth to chase a postseason spot.

• CBS News Philadelphia and MLB.com reporting.