Lee had been on the DL since May 17 with an oblique strain, and was reinstated a day after a one-game rehab assignment at Double-A Bowie.
Lee was in the lineup at first base, batting fifth. He's hitting .231 with four home runs and 14 RBIs.
To make room for Lee, the Orioles optioned left-hander Pedro Viola to Bowie. Viola pitched a perfect 1 2/3 innings in his only appearance.