Blue Jays place Ryu on IL with tight neck
The move comes two days after Ryu said he felt fine following a 7-3 loss to the Minnesota Twins when the hurler only managed to pitch two-plus innings, giving up five earned runs and two homers.
The 34-year-old is in the midst of his worst full season while posting a 4.34 ERA with a 1.21 WHIP over 159 2/3 innings.
The southpaw has struggled lately, allowing 12 earned runs over his past two starts. Ryu's second-half ERA is also 5.61 compared to 3.56 before the All-Star break.
Toronto recalled left-hander Tayler Saucedo from Triple-A to take Ryu's spot on the active roster.