KISSIMMEE, Fla. -- Phillies closer Brad Lidge was slated to be on the bus to play the Astros on Monday, but he stayed back in Clearwater, Fla., because of what general manager Ruben Amaro Jr. characterized as soreness in his right biceps.

Pitching coach Rich Dubee chalked it up as a common issue for pitchers during Spring Training and didn't sound too concerned.

"2011 soreness," he said. "It's a yearly thing, really."

Dubee was unsure whether Lidge would pitch as scheduled in Thursday's "B" game -- something Lidge himself said was doubtful while talking to The Philadelphia Inquirer -- but he added that the 34-year-old is still on track to be ready by Opening Day.

While there's no timetable for Lidge's return to the mound, Dubee said that doesn't necessarily throw him off track, because the right-hander has "already got more innings than he usually has in the spring."

Lidge has made five one-inning Grapefruit League appearances this spring, giving up five runs (9.00 ERA) in the process. In 2008 and '10, he made no appearances while recovering from knee and elbow surgeries. In '09, he pitched in nine spring games and dealt with forearm tendinitis.

Lidge said the recent biceps issue has been bothering him for quite a while, but added that he's "definitely not worried" and it's "a minor thing."

"To be honest, I felt great coming down here, but somewhere in my first outing or two, I just felt a little tightness in my shoulder, and I tried to throw through it a couple times," Lidge told the Inquirer.

"Obviously, it was hard to have great control and improve on arm strength when you're trying to fight through it a little bit, so we just decided [to shut down]. It's not really a major deal. It's biceps tendinitis. We'll let it calm down for a couple days, play catch for a couple days and get back in there soon."

Lidge has said his slider feels good, but his fastball doesn't. During his last outing against the Orioles on Friday -- when he gave up two runs on three hits and a walk -- 19 of his 20 pitches were fastballs, which were reportedly slower than usual.

Lidge told the Inquirer, "That's really just a result of trying to go out there and not really feel very comfortable throwing, because there is some shoulder stiffness."

Since he has made a fair amount of appearances already, Lidge feels he can let the tendinitis subside and still have time to ramp it up by the April 1 opener against the Astros.

"He's just got to work on his path a little bit; his arm action," Dubee said. "Get that straightened out."