BALTIMORE -- The Orioles reached a defining mark in their hunt for a starting shortstop on Saturday, when Baltimore completed a minor trade with Colorado that brought veteran shortstop Juan Castro back to the big leagues. Castro, who had been playing for Triple-A Colorado Springs, was acquired in exchange for Minor League infielder Mike McCoy.

The Orioles won't say whether they consider Casto a full-time option, but executive Andy MacPhail does acknowledge a bit of closure. MacPhail, Baltimore's president of baseball operations, has been through three starting shortstops this season and has widely admitted that he's had an all-out search for infield help for much of the last month.

"We've had many conversations," said MacPhail. "But as you know in the industry at this point, there's a real shortage of middle infielders through a lot of injuries. ... Whatever surplus got eaten up quickly. Juan is someone we had talked to when he had been available early in the year, but Colorado had what they thought was a more immediate need.

"Our [original] interest was to have him in [Triple-A] Norfolk available to us anytime we needed him. He went to Colorado and then pulled a hamstring, and then we had to sort of monitor his progress as to when he'd be prepared to come back. He fits our mold in that were looking for someone who can play defense at that position primarily."

Castro, who began the season with the Cincinnati Reds, was released in early April and wound up signing a Minor League deal with Colorado. The 11-year veteran was batting .300 for the Sky Sox but is a .230 hitter in 930 big league games. Castro has played all over the infield during his career but will likely be earmarked for work at shortstop in Baltimore.

"I havent seen him play, so I think it's too early to say what role he has," said manager Dave Trembley. "The last time I saw Juan Castro play I was managing in the Texas League in 1993, and he was playing for the Dodgers in that league. He just got here. He's been on an All-Star break. I'd like to get a feel for what he can do and then we'll go from there."

"I'm happy," added Castro of his new surroundings. "It was quick the way everything happened but I'm very excited. And this is new, a lot of good guys here. I know some of the guys here so I'm just happy to be here in Baltimore."

McCoy, 27, was batting .276 for Norfolk at the time of the trade. The Orioles outrighted Freddie Bynum to Norfolk to make room for Castro and may need another move when Alex Cintron returns from the disabled list next week. Beyond that, Trembley said the team may continue hunting high and low to find an even better solution at shortstop.

"I dont think you're ever done looking to improve your team," he said. "I probably sound like a broken record but Andy MacPhail has said that you're always looking to improve your club on a continuing basis."