Lee has been limited in workouts while recovering from minor foot surgery to remove a bone spur and was all smiles before and after the 45-pitch bullpen session.
"I'm a pitcher and for me to get here and not go off the mound, that's not a good feeling," he said. "To finally get on the mound and practice what I do, that's where I want to be. It feels good to be doing what everyone else is doing.
"I didn't think at all about my foot, to be honest. I was focused on locating pitches and trying to get my mechanics to where they need to be. The foot thing is basically behind me."
Acquired from the Phillies last Dec. 16 for three Minor Leaguers, including former first-round Draft choice Phillippe Aumont, Lee is expected to follow ace right-hander Felix Hernandez in the five-man rotation, giving the Mariners a powerful one-two punch.
The foot injury which has bothered him for several years but became worse while throwing his one and only pre-Spring Training bullpen session off a mound in Arkansas, put a little scare into the Mariners organization. But the surgical procedure eased a lot of minds, especially those of Lee, manager Don Wakamatsu and general manager Jack Zduriencik.
"When we first heard about it [injury], we were real worried," Wakamatsu said prior to Wednesday's session, "but it probably is a blessing. It's something he's had in the past and we're hoping that it never shows up again."
With pitching coaches Rick Adair and John Wettleland watching, Lee threw 45 pitches to bullpen catcher Jason Phillips.
"I was looking to see if there were any issues with his foot and there weren't any," Adair said. "His arm worked well, the ball came out of his hand well, and when he left he was excited and he felt good from a physical standpoint."
2010 Spring Training - null
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Spring Training Info
Lee was pleased, saying, "I threw all my pitches, but was working more on locating fastballs. I wasn't quite where I wanted to be, but considering the circumstances, I feel good with where I'm at."
The American League Cy Young Award winner in 2008 said it would not take him long to catch up with the other pitchers in camp, adding that "some teams haven't even started going full-tilt yet."
"I'll probably be a little behind [other Seattle pitchers] when I get into a game, but once I get going, I'll catch up," he said. "It's still way early. I knew this was what I was going to have to do, there's no sense in denying that fact.
"I didn't want to do anything that was unnecessary too quick to cause a setback. I understood what was going on and why I wasn't able to take off with everyone else. But I'm a week behind and that's really not that bad at this point."
The next step is to see how he feels on Thursday morning. If there are no unusual aches and pains, he would have another bullpen session on Friday.
"He felt real comfortable and came out of it with no problems," Wakamatsu said. "The plan right now is to take a day off, throw [on Friday] and re-evaluate it at that point. But I am real happy with how he felt today. It was a good sign."
Lee has been playing catch on flat ground since he checked into camp and throwing off the mound was regarded as an important sequence on his recovery from surgery.
Wakamatsu said that throwing off a mound, compared to flat ground, puts 10 to 15 percent more stress on a pitcher's arm "and you can't really prepare for that. Everything has to be done with a progression. He will judge how he feels and how much he turns it up."
The goal is to give Lee and the other starters between 25 and 30 innings during Spring Training and with Wednesday's workout going so well, there seems to be no problem with Lee reaching the targeted figure so he goes into his first regular season start without limitations.