"I didn't want to get overmatched," DeRosa said. "After Dave Bush threw the first pitch, I kind of felt like, yeah, it's a lot harder than batting practice, no doubt about that, but I felt I could get to the ball.
"Now it's nice to forget about it and go back to early work and working on the things for the season."
He had flown to Chicago in late February to undergo a radiofrequency catheter ablation (RFCA). DeRosa, who turned 33 on Feb. 26, was first diagnosed with an irregular heartbeat when he was a teen, and he told the Cubs' medical staff that it has been occurring with increasing frequency.
He rejoined the team one week ago Sunday, but had not been allowed to play in any games to give his leg time to heal and make sure he could move laterally. Part of the procedure involved inserting a catheter into his leg in the groin area.
"He wants to get through that first or second obstacle playing, knowing he can play," Cubs manager Lou Piniella said. "He's been working hard. He hasn't faced any live pitching, and this was live pitching for him. It's going to take him a little bit. Getting at-bats will help.
"We've got all our people back on the field now, and sooner or later we'll get them all on the same field," Piniella said. "It's been awhile and good to see him."
While Piniella would like to see regulars such as Derrek Lee swing the bat a little better -- he's hitting .143 this spring -- he'll give DeRosa a little slack. DeRosa didn't expect to go 3-for-3.
"Obviously, you want to produce and be productive," DeRosa said. "But at the end of the day, that wasn't the main objective. Just to get out there and break a sweat and be with the guys was fun. I knew timing was going to be an issue -- curveballs and stuff.
"I haven't seen live pitching since [the National League Division Series versus] Arizona," he said of the October series. "I didn't strike out [against Milwaukee]. I put three balls in play -- not quality, but I'll take it and build off it."
His timing was a little off. He needs to work on "strike-zone management," DeRosa said. At least he didn't swing at every pitch he saw.
"He's ready to go," Piniella said. "He just needs some at-bats."
DeRosa is expected to play Tuesday, then skip the Cubs' trip on Wednesday to Surprise, Ariz., against his former team, the Texas Rangers. The second baseman said his energy level was fine and that he could've played longer on Monday.
"I felt completely normal, I really did," DeRosa said. "I feel better than normal. What my normal used to be has been enhanced. I feel really good. It was good to be out there, and now it's time to forget about it and work on fundamentals."
The whole procedure was somewhat nerve-wrecking, he said.
"The first three or four days [after the surgery] were rough, just the scare factor of it and dealing with the fact I just had heart surgery and now I'm going to go back and play baseball," DeRosa. "That kind of ended when I got back into the clubhouse with the guys. They help you take your mind off it pretty quick."