The Toronto Blue Jays placed right-hander Brandon Morrow on the 15-day disabled list Wednesday and recalled infielder Yan Gomes from AAA Las Vegas.
Morrow left the game just nine pitches into Monday's start against Washington after suffering a strained muscle in his left side.
A second round of tests Tuesday confirmed the initial diagnosis and Morrow was placed on the DL retroactive to June 12. There is no timetable for his return.
Morrow entered Monday's game having won three of his previous four starts, a stretch in which he also threw two shutouts.
The former first round pick has a career-high three shutouts this season. He's 7-4 with a 3.01 earned-run average in 13 starts.
In 14 games over two stints with Toronto this season, Gomes is hitting .226 with three homers and eight RBIs. He's the first Brazilian-born player in the majors.