Cannizaro was admitted as a hospital outpatient Tuesday, and was given anti-inflammatory medication intravenously to treat a back problem.
Maddon said the problem wasn't serious, and that the IV was necessary because Cannizaro's stomach doesn't tolerate anti-inflammatories well. Maddon said that the medication was needed in order to "expedite getting him back on the field."
Already without the services of utility man Ben Zobrist (fractured thumb), Cannizaro was the front-runner for the job of backing up shortstop Jason Bartlett.
While Cannizaro was not present for Wednesday's early workout or game, Maddon said he expects the infielder to be back on Thursday and get back into a game by Sunday.
Brittany Ghiroli is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.