The Cubs have not yet announced their final roster moves, but Wells confirmed the move to reporters.
The only question remain in the bullpen, where two spots are available but Rodrigo Lopez is the favorite for the long relief role.
Wells was 7-6 with a 4.99 ERA last season. His best year was 2009 when he won 12 games as a rookie.
Travis Wood also was sent down.
Steve Clevenger will be the backup catcher.