Lagrange was diagnosed with a capsular sprain of the right shoulder Friday, Chris Kirschner of The Athletic reports.
Lagrange had been making a push to join the major-league bullpen at some point this season, but he landed on the injured list at Triple-A Scranton/Wilkes-Barre on Thursday and is now facing an extended absence following his diagnosis. The Yankees will keep him shut down from throwing for about six weeks, at which point he'll be re-evaluated.