The Mets will pay a portion of Castro's remaining salary.
The trade satisfies the Mets' dilemma at catcher, where with the impending return of Brian Schneider, the team had three players for two spots. Omir Santos, who started the season in the Minors, had apparently passed Castro on the depth chart -- an ascension reaffirmed when Santos drove in both Mets runs, including the game-winner in the 11th, on Friday.
"On a night like tonight when Omir Santos plays the way he did, it makes the decision easier," said general manager Omar Minaya after the game.
Castro had served as the Mets' backup catcher since 2005. He hit .253 in 26 games for the team this season -- one point higher than his career average with the club.
Broadway, a first-round pick in 2005, was 0-1 with a 5.06 ERA as a reliever for the White Sox. He will be assigned to Triple-A Buffalo, where he will be placed in the starting rotation.
The Mets had to make a move with one of their catchers with Schneider, the Opening Day starter, ready to be activated from the disabled list Saturday. Santos was the only one of the three with Minor-League options remaining but had earned his spot in the lineup according to manager Jerry Manuel.
"Santos will be on this team in some form or fashion," Manuel said after the game but before the Castro trade was announced. "No doubt about that. He's represented himself too well as a Major League player and as a Major League hitter."
At no time was that clearer than Friday night. Santos hit an 0-2 fastball from Florida's Sean West for his third home run of the season in the fifth inning before driving in Gary Sheffield with the winning run in the 11th on a single to left field.
"He's hit well in the clutch," Manuel said. "There's no panic or anxiety when he's in those situations."
The Mets considered carrying three catchers on the everyday roster until they were able to reach the deal with the White Sox.
Tim Britton is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.