Gelof hasn't played for Double-A Midland since May 26 while recovering from a torn labrum in his left shoulder, Melissa Lockard of The Athletic reports.
Gelof suffered the injury in question after landing awkwardly while diving at a groundball. Since the labrum tear is in his non-throwing shoulder, Gelof will avoid what likely would have been a season-ending surgery, but the 22-year-old third baseman should still be viewed as out indefinitely. Before getting hurt, Gelof produced a .315/.372/.458 slash line with four home runs and eight stolen bases across his 183 plate appearances with Midland.