Right-hander Chris Tillman made it through his first rehab assignment at a club affiliate Monday night, lasting 2 2/3 innings for Double-A Bowie against Richmond, the San Francisco Giants affiliate.

Tillman, attempting to come back from a shoulder injury that has affected him off and on since September, allowed one run on two hits and a walk while striking out three batters. He threw 42 pitches – roughly what the Orioles had outlined – including 25 for strikes.

The only run he surrendered was a solo homer to right field to the second batter he faced, 25-year-old second baseman Carlos Garcia. Before facing Garcia, Tillman struck out the Flying Squirrels leadoff hitter, Slade Heathcott, on three pitches.

Pitching two days after his 29th birthday, Tillman retired six in a row before allowing a one-out walk and a single to Heathcott. He got Garcia to fly out and then was replaced by reliever Lucas Long, who induced a pop-up to preserve Tillman’s line. Tillman mixed in all of his pitches, with his fastball hovering around 90 mph.

This is basically the kind of outing the Orioles were hoping for with Tillman: Uneventful. They figured he’d go 45 pitches or three innings and build on this one the next time out. He’s expected to pitch this weekend in Frederick — initially he’ll be alternating affiliates to stay within an easy drive of Baltimore.

The hope is that Tillman, the Orioles’ No. 1 starter, keeps building arm strength without suffering any right shoulder discomfort and can be back pitching in the big leagues by the first week or two in May.