Olson, who gives A's manager Bob Melvin a five-man bench against the National League host Mets, is back for a fifth time with Oakland this season, having hit .225 with four home runs and eight RBIs in 10 games in his most recent stint. Olson was averaging one home run per 13 at-bats with Nashville.
Montas, meanwhile, returns to the A's bullpen following a stint as a starter in Nashville, where he went 0-1 with a 4.