The surgery that Wheeler will have involves removing a rib. Doctors say he’s facing a long and potentially challenging recovery.

Dr. Cherie Erkmen, a thoracic surgeon at Temple University, is not treating Wheeler and spoke with CBS News Philadelphia about the procedure.

“Thoracic outlet syndrome can manifest in many different ways,” Erkmen said. “It’s when the first rib has pressed on either the nerve, the artery or the vein.”

Wheeler’s condition centers in the thoracic outlet area, which is between the collarbone and the first rib in the top part of the chest.

“People like rowers or pitchers, even occupations like painters and hair stylists, people who have their arms up and doing repetitive motions, that you can develop this really strong muscle in the neck and it hoists that first rib up,” Erkmen said.

Erkmen said that it can cause a variety of symptoms, including numbness and tingling.

The Phillies announced Saturday Wheeler’s treatment will be thoracic outlet decompression surgery — the removal of the first rib just below the collarbone. There are several different ways to do that.

“One of them is through an incision above the clavicle, another one is through an incision in the armpit in the axilla, and another one is robotically — to go into the chest and remove it from the inside out,” Erkmen said.

The Phillies have not disclosed the kind of surgery Wheeler will have or when or where, but it will sideline him for 6 to 8 months.

The Phillies’ head trainer has said Wheeler could be throwing eight weeks after surgery because his condition does not involve nerve damage. If everything goes OK with his recovery, he could be back on the mound next season.