Gelof (knee) started at second base and went 1-for-3 with a three-run home run with Triple-A Las Vegas on Tuesday.
Gelof made his first rehab appearance since hitting the shelf July 10 due to a right knee laceration and crushed a three-run shot in the fifth inning. The expectation is that the 26-year-old will need about 20 MiLB at-bats before returning to the big-league club, per MLB.com. He started Tuesday's contest at second base but has spent much of the season with the Athletics at third base, with the versatility to play just about anywhere in the field. Before landing on the injured list, Gelof slashed .273/.327/.476 with 11 home runs, 29 RBI, 41 runs and eight stolen bases across 67 games.