"Derrek Lee spent less than half of a season with the Atlanta Braves in 2010, joining the club via trade. But Pirates outfielder Matt Diaz , who played with Lee in Atlanta, said the first baseman immediately became a leader.

"When he walked in Atlanta's locker room, even with the veterans we had last year, he was the instant go-to guy," Diaz said.

He expects Lee to have the same type of effect in the Pirates' clubhouse as he prepares to welcome Lee to a new team for the second time in a little more than a year. The Pirates acquired Lee in a trade Saturday, which sent minor leaguer Aaron Baker to the Baltimore Orioles.

Lee will join the Pirates today at PNC Park, surprising some that he did not travel from New York, where the Orioles were playing, to Philadelphia for Sunday's game.

"I know a lot of people thought he'd be here [Sunday], but knowing what a family guy he is, I had a feeling he would not be here [Sunday], and I'm proud of him for showing up Monday," Diaz said.

Lee's daughter Jada cannot see out of her right eye. She was initially diagnosed with Leber's Congenital Amaurosis, a rare disorder that results in vision loss. Lee became an advocate for the disorder, encouraging people to get tested. He continues his involvement, even after learning his daughter was misdiagnosed."