Knuckleballer R.A. Dickey (8-13, 4.51 ERA) will start for the Blue Jays in their first meeting this season with the Angels, who will turn to left-hander Tyler Skaggs (1-2, 5.19 ERA).
Pillar injured his left thumb on a slide into second base on Aug. 7 in Kansas City. He likely will be reinstated from the disabled list after going 6-for-7 with a double and two RBIs in two games for Class A Dunedin on a rehabilitation assignment.
The move will give the Blue Jays more flexibility in the outfield. Melvin Upton Jr. has been playing center field in Pillar's place and recently has started to find himself at the plate.
Upton has batted .333 (6-for-18) with three home runs and six RBIs in his last five games. When Pillar returns to play center, it means Upton can move to one of the corners, probably right field with Michael Saunders returning to his regular spot in left field.
Ezequiel Carrera would resume his role as the team's fourth outfielder.
It is not certain when Jose Bautista will return from a sprained left knee. He is eligible to return from the disabled list on Thursday for the final game of the series