After being acquired from the Mets in an August 9 trade, Cleveland outfielder Jay Bruce hit.375 with three homers and 12 RBIs during an 11-game trip as the Indians went 8-3.
According to an industry source, the left-hander was examined Monday for a possible ulnar nerve issue in his left elbow that could require season-ending surgery.
The club announced that the surgery would be scheduled within the next few days.
Matz has been one of the worst pitchers in baseball this year, running up a 6.08 ERA in 13 starts this season. He has been hit hard lately, going 0-6 with a 10.19 ERA in his past eight starts.
In May 2010, Matz had Tommy John surgery to fix a tear of his left ulnar collateral ligament.
Matz's season also ended prematurely past year due to a shoulder impingement followed by surgery to remove a bone spur from his elbow. Both he and Gallo are experiencing concussion symptoms, Evan Grant of the Dallas Morning News reports, and Gallo also suffered a nasal fracture. Gallo suffered a nasal fracture and missed Monday's game.
Matz began the season on the DL with elbow discomfort, but returned to pitch in early June.