Baltimore, MD -- (Sports Network) - The Orioles and Rockies exchanged minor league infielders on Saturday, with Baltimore acquiring Juan Castro and Colorado netting Mike McCoy.

Baltimore selected Castro's contract from Triple-A Norfolk and outrighted infielder Freddie Bynum to its minor league affiliate to make room for the veteran.

Throughout parts of 14 seasons, Castro has spent time with the Dodgers, Twins and Reds, who released him earlier this year before he signed a minor league contract with the Rockies. Castro has hit .230 in 930 career games, but went hitless in 10 at-bats for Cincinnati prior to his release.

McCoy, who was acquired via trade with the St. Louis Cardinals in March, hit .276 in 53 games with Norfolk, while Bynum struggled to a .179 average in 40 games with the Orioles this season.

In other moves, the O's activated pitcher Randor Bierd from the disabled list and placed pitcher Greg Aquino on the 15-day DL.

Bierd was put on the disabled list on May 2, retroactive to April 30, with right shoulder impingement. He allowed three runs in 13 1/3 innings of work before the setback, and registered a 2.77 earned-run average in 11 rehab outings before being activated.

Aquino has a left hamstring strain and will be placed on the DL retroactive to July 13. He has posted a 12.54 ERA in nine games with the big club this season.