Wheeler (shoulder) threw a successful bullpen session Monday and is scheduled for another session Thursday, Scott Lauber of The Philadelphia Inquirer reports.
It represents Wheeler's first time throwing off a mound since the shoulder soreness surfaced in December, and he's a bit behind schedule to open spring training. The 31-year-old has already been ruled out as a possibility to start Opening Day, though there's still a chance he'll be ready sometime during the first week of the season, per Jim Salisbury of NBC Sports Philadelphia. The shoulder soreness doesn't appear to be an ongoing issue, but the late start to throwing will affect Wheeler's outlook for the beginning of the regular season.