FORT MYERS, Fla. -- When he first donned a Red Sox uniform this week in Fort Myers, Sean Casey was like a child opening a present. But as the Red Sox are finding out, Casey's personality is the gift that keeps giving.

On Feb. 5, when the Red Sox and Casey finalized a one-year, $800,000 contract, Casey was introduced at Fenway Park and the Red Sox quickly discovered why the 33-year-old first baseman has earned one of the most appropriate nicknames in baseball.

"The Mayor" continued his stumping Friday during the first full-squad workout at the Red Sox's Minor League complex.

"Wow, I'm excited, I really am excited," Casey declared. "To be a part of this and even to just put on stuff that has 'Red Sox' on it is pretty cool. If you're a baseball player and if you have any spirit toward the game, everyone wants to play, at some point, their career in Boston. For me to be here and a part of this, I'm excited."

Captain Jason Varitek, not known for his impersonations, offered one when he broke out a huge grin while recalling his first meeting with Casey at camp this week.

"I talked to him, and he's so excited," Varitek said. [He said,] "'Wow, the fans are out here!' He was really excited. Sean can swing the bat. From what all we know about Sean Casey, there's no better teammate than Sean Casey, from everybody I've ever spoken to."

Casey, an NCAA batting champion with the University of Richmond, was drafted in the second round of the 1995 Draft by Cleveland. He was traded in April 1998 to Cincinnati, where he made his name as "The Mayor" and as one of the best clutch hitters in the game, leading the Reds to 96 wins in 1999.

Seeking pitching, the Reds dealt Casey to Pittsburgh in exchange for left-hander Dave Williams in December 2005. Casey played for his hometown Pirates for just half a season before being dealt to the Tigers at the July trade deadline in 2006 and helping the Tigers to the American League pennant. Casey left Detroit after last season and signed with the Red Sox as a free agent.

"He's a great guy, and I think it will help the chemistry of this club to have such a respected player and well-liked player who has never won a ring," Red Sox general manager Theo Epstein said. "Coming off a year in [which] we won a World Series, his passion and his hunger to be a world champion might rub off some day in August when it's hard getting out of bed. Having him around might really help.

"First and foremost, his ability to hit good pitching and step in if we do suffer an injury at either corner infield position -- because of [Kevin] Youkilis' ability to go to third -- we feel protected."

As impressive as his career .301 average is over 10 big league seasons, Casey brings a reputation as one of the best clubhouse influences in the game.

"He's that way every day," Red Sox manager Terry Francona said. "He brightens up a room, brightens up a field, and it's legit. I think Mike Lowell was saying he's a good teammate, but the other players like him, too. He's a guy, when there's a fight, you're never going to see somebody take a swing at him. He's a good guy."

Nobody brightens up a room quite like David Ortiz, who upon seeing Casey this week lifted him up off the ground and gave him a bear hug. And now, Papi's smile has competition from Casey's charisma. It's no mistake that the two have been close since their days in the Minor Leagues, Ortiz with Minnesota and Casey with Cleveland.

"Me and Papi go way back, to '97," said Casey. "I think sometimes with the guys you play in the Minors with, when you get to the big leagues with them, you always have that connection. So we always did, even when he was with the Twins, we'd always get together and talk and everything like that. So, I've gotten to know Papi pretty well over the years."

Then there's the story Francona tells about the day he and Casey met at Cal Ripken's baseball fantasy camp in Arizona.

"I was at a fantasy camp with him, Cal Ripken's fantasy camp -- a pretty long time ago -- and actually, I saw somewhere where he said something about I said to him, 'Someday you're going to play for me,' because I said that to him. And I also told him, 'If there's a day I see you change, I will personally kick your [butt],' Francona said. "Because to me, he was the perfect player: smile from ear-to-ear, treats everybody like they're the most important person in the world, respects the game, and he hits .300. He's a good kid."

"It was either '99 or 2000, and we were out in Arizona and we did a fantasy camp," Casey confirmed. "It was funny, too, because at Cal's Fantasy Camp, Tito was one of the managers, [Jim] Leyland was one of the managers, [Mike] Hargrove was one of the managers, Tom Kelly, it was like the All-Star managers were out there at Cal's camp."

The fact Casey is the only significant position player acquired this offseason speaks volumes about how much Epstein and Red Sox management felt about Casey and his potential impact on a defending World Series champion.

"When you don't make a lot of changes and you bring back a lot of your same team, you know you're pretty good," Casey said. "With Detroit, they did the same thing. We went to the World Series in 2006, and they brought in [Gary] Sheffield, which made it even better. When you don't bring in too many guys, you know you're pretty good."