The Orioles activated second baseman Brian Roberts from the 60-day disabled list and optioned infielder Steve Tolleson to Triple-A Norfolk on Tuesday.
Roberts had been on the disabled list since May 17, 2011 because of concussion symptoms.
The 34-year-old Roberts has not played a full season since 2009 and has .281 average and 84 home runs in his 11-year career.
Tolleson hit .237 with two home runs in 38 at-bats with the Orioles this season.
To make room for Roberts on the 40-man roster, Baltimore transferred outfielder Nolan Reimold to the 60-day DL. Reimold has been on the disabled list since May 1 with a herniated disc in his back.