GOODYEAR, Ariz. -- As Reds pitchers work in bullpen sessions, reliever Nick Masset is unable to join them. Masset, who missed all of last season, is still rehabilitating from right shoulder surgery he had in September.

Masset began a throwing program in January, and until recently was only playing catch three times a week. But it's been slow going.

"Now I'm starting to build up to throwing every day," Masset said on Thursday. "It's not exactly where I want it to be right now. But I understand that it is a process. I'm really going to have to grind through the aches and pains to build arm strength to get my arm able to throw consistently without having any setbacks."

Masset's throwing program is slated to last at least three months before he can return to game action. It's unclear when he can begin working from a mound again.

"I don't have a crystal ball right now," Masset said. "Being here every day, grinding it out and working hard with the doctors and trainers and everyone helping me out, it will be the key to getting me back on the field."