Blue Jays manager John Farrell said Thursday that the 30-year-old right-hander experienced some soreness in his shoulder during long tossing. McGowan underwent an MRI and has consulted with orthopedist Dr. James Andrews.
Farrell said the test confirmed there was inflammation but no new damage.
McGowan, Toronto's first round draft pick (33rd overall) in the 2000 draft, has a history of shoulder and knee injuries and spent most of the previous three seasons on the disabled list. He opened this season on the 15-day disabled list after being diagnosed with plantar fasciitis.
He is 20-24 with 4.80 ERA in 80 games, 60 of them starts, over parts of five seasons.