The Blue Jays placed Bieber on the 15-day injured list Tuesday with right teres major inflammation, Arden Zwelling of Sportsnet.ca reports.
Bieber had shown no signs of being hurt, having allowed a combined two runs with a 12:2 K:BB over 13 innings covering his last two starts. While he will be eligible for activation in early September, the nature of the injury could make it difficult for Bieber to return before the end of the season.