ST. PETERSBURG, Fla. -- Tampa Bay Rays All-Star left-hander Shane McClanahan might not pitch again this season.

Rays manager Kevin Cash said before Tuesday night's game against the St. Louis Cardinals that McClanahan will have his injured left forearm evaluated by another specialist soon but it is "highly unlikely" that he will pitch again this season.

Cash said Tommy John surgery, flexor surgery or loose body removal are among the options under consideration.

"Less than ideal news," Cash said, "I think at this point probably everything is on the table. Surgery is certainly an option."

McClanahan missed the 2016 collegiate season at the University of South Florida after having Tommy John surgery.

McClanahan is 11-2 with a 3.29 ERA in 21 starts this season. He left his last start on Aug. 2 in New York against the Yankees with tightness in his left forearm. He pitched four innings and gave up five runs. The 26-year-old has pitched five innings or less in five of his past six starts.

McClanahan is scheduled to see orthopedic surgeon Dr. Keith Meister for a second opinion next Monday. He was already examined by Los Angeles-area surgeon Dr. Neal ElAttrache on Monday.

McClanahan is 0-1 in six starts since his last win on June 16, leaving starts on June 22 and 30 due to mid-back tightness that eventually forced him onto the 15-day IL on July 1. He returned July 17 and went six innings against Texas before lasting just four, five and four innings in his next three starts.

Tampa Bay, the AL wild-card leader, has gone 16-21 entering Tuesday since the start of play on June 22.

McClanahan joins a lengthy list of Rays rotation members sidelined heading into the final stretch of the regular season.

Jeffrey Springs (Tommy John surgery), Drew Rasmussen (elbow ligament internal brace surgery) and Shane Baz (Tommy John surgery) are out for the year. Josh Fleming (left elbow inflammation) is currently on a rehab assignment with Triple-A Durham.

Tyler Glasnow, scratched from his start Sunday at Detroit due to back spasms, received an injection Tuesday. Cash is hopeful the 6-foot-8 right-hander will be able to pitch this weekend against Cleveland.

"We're optimistic he will respond," Cash said. "Over the next two days let's see how he responds, and then we'll look to reinsert back into the rotation."

The Associated Press contributed to this report.