Romero began the season with St. Louis, going 0-0 with a 10.13 ERA in 11 games before being released May 14. He was signed to a minor league contract by the Orioles and went 1-0 with a 2.51 ERA in 17 appearances for Triple-A Norfolk. He was then signed by the Indians to a minor-league deal July 21 and pitched in eight games for Triple-A Columbus.
Romero's contract will be purchased Tuesday, and he will be added to the 25-man roster, according to the Orioles.
He is 34-28 with a 4.15 ERA over a 14-year career.
Rojas batted .226 in 48 games with Double-A Bowie and Norfolk this season.