Quintana (elbow) is scheduled to throw a bullpen session Wednesday, MLB.com reports.
Quintana most recently tossed a 23-pitch bullpen session Sunday that consisted of all fastballs and changeups. The veteran southpaw -- who has been on the shelf since May 25 due to an elbow sprain -- could soon be cleared to face hitters and appears to be tracking toward a return to the Rockies' active roster in late August or early September.