CLEARWATER, Fla. — The first one went swimmingly, so the Phillies are aiming for Sunday for Zack Wheeler to throw his second bullpen session of the spring.

It will be a 25-pitch session of fastballs and some splitters, manager Rob Thomson said after Friday's 10-2 win in Clearwater over the Marlins.

Wheeler has incorporated breaking balls when throwing off of flat ground but not yet off the mound and that will wait until at least his third bullpen session. The Phillies give their pitchers two days off in between, so Wheeler's next two 'pens could end up being Sunday and Wednesday. The next step from there could be pitching live batting practice.

Wheeler was encouraged by how he felt after throwing 21 pitches off a mound Thursday, and while he won't offer specifics, he didn't rule out a mid-April return. The ace missed the Phillies' final 40 games and the NLDS last season after being diagnosed with venous thoracic outlet syndrome, for which he underwent surgery on Sept.…