"Wes had severe cramping, and medically, he shouldn't play today," manager Bob Geren said. "He's available to pinch-hit, though."
Bankston was recalled from Triple-A Sacramento prior to Saturday's game when Daric Barton was placed on the 15-day disabled list with a neck strain. Bankston went 2-for-5 with one run scored and three strikeouts before leaving.
Jack Hannahan took Bankston's spot at first base on Sunday, and Geren said that Emil Brown would be the likely backup if needed.
But Geren hasn't ruled out Bankston as an option.
"I could probably put Bankston in depending on the situation, with what inning we're in and what I need," he said.
Bankston has a .294 batting average over nine games with the A's and hit .214 in three starts with Sacramento after being optioned on July 10.
Samantha Newman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.