CLEARWATER, Fla. -- Phillies setup man Mike Adams had reason to be concerned earlier this week when he felt some discomfort in his right shoulder.

Adams has had his share of injuries and surgeries the past couple years. He had thoracic outlet syndrome surgery in October 2012, right shoulder surgery in July '13 and sports hernia surgery in October '13. Adams has been rehabbing from those surgeries, and he threw his first bullpen session of the spring Thursday morning at Bright House Field.

It was an important step in Adams' recovery.

"It went good," Adams said. "Real good. It was probably an 85 percent bullpen [session] or so. Especially being the first one, I wasn't trying to let loose right off the bat. I wanted to make sure I got a good feel for throwing off the slope again and finding my arm slot. It felt good."

But Adams said his arm felt "iffy" when he threw off flat ground Monday.

"Just uncomfortable," Adams said. "It was the first time. That was the first time in this whole process that I've had any type of discomfort. Today felt back to normal. ... When you've been through what I've been through as far as injuries and shoulder stuff and any kind of discomfort, it gets in the back of your head. I talked to [head athletic trainer Scott Sheridan] the other day and he's like, 'Hey, you've got every right to panic a little bit. What you've been through, it's normal. It's OK. You're fine.'

"That's probably going to be the biggest struggle for me. Before I came out here, I was nervous. I was worried. Everything's an unknown. I don't know how it's going to go. It seems like every time I'm going out there, I'm hoping for the best. Just trying to stay positive. Every pitch could be the last pitch. Right now, I'm just kind of counting my blessings and going day by day. Every time I get through something, it's just another checkpoint that I've hit."

Adams will throw his next bullpen session Sunday. He believes he could pitch in a Grapefruit League game sometime in mid-March. Adams has said he could back in the Phillies' bullpen sometime in April, but there are no guarantees following shoulder surgery.

"I don't know velocity-wise where I'm going to be," Adams said. "I don't know if I'm going to be 84-85 [mph] or 89-90. That's going to be the most important thing that I do, command the ball and keep the ball down and change speeds. I think it's going to be very important this year that I use my changeup just to keep them off balance a little bit.

"The more velocity I have, the better. But I'm not going into this thinking, 'You're going to have no velocity.' Whatever happens as far as that goes, it's going to be a bonus."