SURPRISE, Ariz. -- Early camp shoulder soreness has already made Reds ace Luis Castillo unlikely to be ready in time to be part of the Opening Day roster. A similar issue has now occurred with newly added left-handed starter Mike Minor.

Minor, who was acquired from the Royals for reliever Amir Garrett on March 16, experienced his soreness after a throwing session last week. Like Castillo, he feels fine now, but there aren’t enough days to ramp up the throwing program to be able to start games early in the regular season.

“I’ve dealt with it before,” Minor said on Thursday. “We had the extra days to deal with it. Now you don’t, so everything is magnified. Guys are trying to play through some stuff right now, get some treatment and keep on going. We don’t have the luxury now of having extra days. I think a lot of teams are going through that.”

Spring Training was shortened to 3 1/2 weeks following a 99-day lockout and the season is set to open on April 7.

“It’s getting a little late in camp to think about them starting the season on Opening Day with our team,” Reds manager David Bell said of Minor and Castillo. “Not all the way there yet, but it’s starting to look that way. We have to do the smart thing for those guys. If they start the season on the IL and have to miss a week or 10 days, that could be a pretty good tradeoff.”

Minor is scheduled to throw in a side bullpen session on Friday and he will look to eventually progress to facing hitters in live batting practice before getting into a Cactus League or Minor League game.

“If it was a normal camp, you’d have built-in days or built-in weeks, so you don’t have to rush,” Minor said. “Even when I’d have a healthy Spring Training, usually you’d take a step back because you have so many starts, it’s almost like, ‘You’ve already built up to five innings but let’s repeat that again.’ Or they might give you an extra day [off].”

“It seems like no matter how much you do at home, and you get here and I haven’t had contact with anybody [because of the lockout]. You can’t tell anybody what’s going on or how you feel. Then you get here. You try to do your best while you’re at home by yourself. But you get your Spring Training aches and pains all the time. It’s kind of part of the process.”

With Minor and Castillo likely out and the fifth starter role already being a competition, the Reds will need to cover three spots early.

One of the contenders, No. 2 prospect Nick Lodolo, faced the Royals on Thursday and pitched 2 1/3 innings. He allowed one run, four hits and a walk while striking out two. In two spring starts, Lodolo has a 2.08 ERA.

Also battling for rotation spots are top prospect Hunter Greene, No. 8 prospect Graham Ashcraft, No. 30 prospect Reiver Sanmartin and right-hander Tony Santillan.