He had been slated to undergo an MRI to determine the extent of the injury.
Ryu is 2-0 with a 5.33 ERA in six starts. He missed 24 games in April and May because of soreness in his forearm but had gone 2-0 with a 1.72 ERA in his past three starts since returning May 14 at Tampa Bay.
He left his previous start, May 26 against the Los Angeles Angels, after five innings because of a sore elbow. Ryu said Wednesday through an interpreter that the current injury feels "more similar to earlier in the season when I was hurt."
In a corresponding move, the Blue Jays called up right-hander Jeremy Beasley from Triple-A Buffalo. Beasley is 0-1 with a 7.45 ERA in nine career major league appearances, including eight last season for Toronto.
The Associated Press contributed to this report.