Castro was acquired by the White Sox from the Mets, along with cash considerations, in exchange for right-handed reliever Lance Broadway as part of a deal announced following Friday's 11-2 victory over the Royals. The 33-year-old provides an upgrade both offensively and defensively behind starter A.J. Pierzynski, with Castro's 13 RBIs as part of the Mets standing as two more than Pierzynski has to date.
Castro's strong arm also will serve as a bonus, as he has thrown out six of 14 attempted basestealers in 2009, and has a 27.7 percent success rate for his career. White Sox catchers are a combined 2-for-43 in throwing out would-be basestealers, but a large share of that problem can be traced to the inability of White Sox pitchers to consistently hold on runners.
"I'm a backup," said Castro of defense being a priority, adding that he already caught three pitchers in Saturday bullpen sessions to learn about what they threw. "Every time I go out there, I care about hitting, but I care more about the pitching.
"Maybe I go 0-for-4, strike out three times and I throw the guy out at second and we win the game. It makes me feel better. That's the kind of guy I am."
He's the kind of guy who has the talent to be an everyday player, but has accepted and flourished in a reserve role.
"I know he's the catcher," said Castro, pointing across the room at Pierzynski during the interview. "When he needs a day off, I'll be there playing and hopefully we win some games."
Manager Ozzie Guillen won a World Series title with Castro and the Florida Marlins in 2003, with Guillen serving as the team's third-base coach before taking charge of the White Sox. Castro is happy to be reunited with Guillen and hopes to share another championship celebration.
"Oh, my god. Fun. Crazy and I love it," said Castro, when asked what it was like being with Guillen as part of the Marlins. "I had a feeling something was going to happen. I'm glad I'm here with Ozzie. I'm here to win."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.