He returns to a division where he is familiar, having played for the Cubs the past two years. He also returns to playoff contention, leaving a Cleveland team that has disappointed.
"You're disappointed because you want to hit the rewind button and start over here," he said. "I was just starting to get comfortable and get to know the guys. That's the toughest part. But I have a chance to play for a division title again and put myself in a great situation with a new team. I'll say my goodbyes and move on."
DeRosa, 34, is hitting .270 with a .342 on-base percentage and a .457 slugging percentage. He has largely played third base for the Indians and is expected to do the same in St. Louis, but his versatility is one of the traits that makes him appealing to the Cardinals. If Troy Glaus does return from offseason shoulder surgery -- and that remains an unknown -- DeRosa could play second base or the outfield.
"I think the nice thing about him is he can play third, he can play the outfield and he can play second base," general manager John Mozeliak said. "So he gives us a lot of flexibility. The big thing for us is the right-handed bat in our lineup. The balance of that will be a nice injection to our club."
A University of Pennsylvania product, DeRosa is in the final year of a three-year deal that pays him a guaranteed $5.5 million in 2009. He has raked left-handed pitching this year, posting a line of .339/.409/.661 against lefties. The Cardinals, meanwhile, rank second-to-last in the Major Leagues in batting average and slugging percentage against lefties, and fourth from the bottom in on-base percentage.
DeRosa is also highly regarded as a teammate and clubhouse presence, and the Cardinals know him well from facing him during his tenure with the Cubs.
"We've always admired him as a player," Mozeliak said. "The way he goes about his job is very professional, and when you look at what or club needed, we felt like he would be a great addition to this organization."
It became evident a move might be in the offing when DeRosa was held out of Cleveland's lineup on Saturday.
"I've been reading [trade rumors] every night," he said. "When the lineups went up today, I thought something might be up. I've been reading too much stuff to not think that something would eventually happen."
Perez, who turns 24 next month, is a hard-throwing reliever once believed to be the Cardinals' closer of the future. In 29 appearances this year, he is 1-1 with a 4.18 ERA, 30 strikeouts and 15 walks in 23 2/3 innings. However, the Cardinals are deep in right-handed relief, and Perez appeared to have been passed on the depth chart this year by Jason Motte.
A deal centered on DeRosa and Perez had appeared to make sense for quite some time, and had long been rumored. DeRosa addresses the Cards' most immediate needs, and his ability to play multiple positions makes him an ideal player for manager Tony La Russa. Cleveland, meanwhile, bolsters a bullpen that has been a sore spot all year.
"There was motivation on both sides," Mozeliak said. "When it was all said and done, it was something that we didn't want to see go away if we waited any longer. A lot has been made about how we've dealt with trades over the past year and half or so. This was something we were very reactive to. Rather than try to drag this out and see if our offense got better or see if we could get closer to the July 31 date, we though it would be best to be proactive."
Mozeliak declined to declare whether the Cardinals are now unable to make any more significant deals before the July 31 non-waiver Trade Deadline.
Also unclear is what the move means to Khalil Greene, who had moved to third base upon his return from the disabled list. The Cardinals have been pleased with the play of Brendan Ryan and Tyler Greene, who stepped into the void when Khalil Greene received treatment for social anxiety disorder.
DeRosa will wear uniform No. 7 and is expected to join the Cardinals in time for their Sunday game at home against the Twins.