That means Brad Bergesen will begin the season in the bullpen, but would be the leading candidate to start April 10, when the team needs a fifth starter.
Tillman, 22, was 2-0 with a 3.93 ERA in five games, four starts, this spring. He allowed 20 hits and nine walks while striking out 10 in 18 1/3 innings.
He obviously will be on a short leash with both Justin Duchscherer (disabled list) and Zach Britton (minors) targeting late April for their Orioles’ debuts.
Bergesen, whose last spring start was cut short Friday when he took a liner off the right forearm, was 1-1 with a 5.82 ERA in six starts. He allowed 25 hits and six walks while striking out seven in 17 innings.
He threw two innings in a simulated game Wednesday against Orioles’ minor leaguers.