Jeremy Guthrie has allowed one hit and walked a batter in three innings in his first start since April 1. His fastball is clocked at 91-92 mph.
Adrian Beltre reached on Mark Reynolds' throwing error leading off the second. Ian Kinsler lined a single to center with two outs in the third and Michael Young walked on four pitches.
Josh Hamilton followed with a long drive to right, but Nick Markakis made a nice grab against the fence to end the rally. Markakis didn't budge for a few seconds before racing back on the ball, reaching over his head and making the catch.
Guthrie, hospitalized last week with pneumonia, has thrown 35 pitches so far. Manager Buck Showalter didn't mention any restrictions on Guthrie, saying the Rangers would determine how long the right-hander stays out there.
Guthrie hasn't allowed a run in 11 innings this season.
The Orioles have two hits off Texas left-hander Derek Holland - back-to-back singles by Derrek Lee and Vladimir Guerrero in the first.
Update: Adrian Beltre barely missed a home run leading off the fourth, the ball hooking foul, but he connected for one on the next pitch. Rangers 1, Orioles 0.
Guthrie had thrown 54 pitches, 30 for strikes.
Vladimir Guerrero is 2-for-2 with a double. Both hits have gone to right field.