Tyson Ross will have an MRI on his ailing shoulder

AP Photo/Tony Gutierrez

Padres pitcher Tyson Ross hasn’t pitched since his season debut against the Dodgers on April 4 due to shoulder inflammation. He hasn’t made much progress in the two weeks since, so the Padres will have the right-hander undergo an MRI, per Dennis Lin of the San Diego Union-Tribune.

The woebegone Padres certainly can’t afford to lose a pitcher of Ross’s caliber. They enter Wednesday night’s game against the Pirates at 5-9 with the fifth-worst starting rotation ERA in baseball at 5.15.

Robbie Erlin has been starting in place of Ross. He made one solid start against the Phillies, allowing one run in six innings, and a rocky start against the Diamondbacks in which he served up six runs in six frames.