The chances of Trevor Rosenthal taking the mound for the A’s any time soon is in serious doubt.

Rosenthal underwent surgery on Thursday after being diagnosed with severe neurovascular compression, the club announced. He was transferred to the 60-day injured list. The surgery, which was performed by Dr. Gregory Pearl at the Baylor Scott and White Heart and Vascular Hospital, involved the removal of his first rib, a pec minor release and scalene release. Rosenthal will receive a check up in about eight weeks.

Rosenthal, who signed a one-year, $11 million deal with the club in February, entered the season with high expectations to replace former All-Star closer Liam Hendriks. After getting a late start to Spring Training, due to a groin strain, he appeared in four Cactus League games and posted a 2.25 ERA.

Closer Trevor Rosenthal and the Oakland Athletics are in agreement on a one-year, $11 million contract, sources familiar with the deal confirmed to ESPN on Thursday.

Rosenthal, 30, had been seeking a four-year contract, but the free-agent market for relief pitchers had cratered. He did have multiyear options, sources told ESPN’s Jeff Passan, but he chose the higher annual salary and save opportunities that Oakland offered.

The right-hander was 1-0 with 11 saves and a 1.90 ERA in 23 relief appearances last season for Kansas City and San Diego, which acquired him on Aug. 29. He joined the Padres in the middle of a rebound season after struggling with injuries and poor performance in recent years.