Triple-A Norfolk placed Willems on its 7-day injured list Thursday due to a left hamstring injury, Jake Rill of MLB.com reports.
Willems has been serving as Norfolk's top backstop this season, compiling a .261/.359/.449 slash line with 14 home runs through his first 69 games before landing on the shelf. The Orioles haven't revealed a timeline for Willems' return, but he'll most likely be held out of action through the All-Star break.