Manager Terry Francona said the team wanted Buchholz a chance to get the "rust" off.
Buchholz, who strained his left hamstring running the bases in late June, gave up a home run, committed a balk and hit a batter for the Red Sox. In all, he pitched 3 2/3 innings, giving up two runs on four hits, walking one and striking out two.
He threw 60 pitches, 33 strikes, to the 16 batters. He's on track to pitch Wednesday afternoon in Oakland. PawSox broadcaster Dan Hoard said Buchholz registered 96 mph on his fastball.
The Red Sox started left-hander Felix Doubront, who left in the fifth after his second throwing error put two runners in scoring position with one out. Doubront ended up with the loss as the Rangers defeated Boston 8-4 behind Bengie Molina's cycle, which included a grand slam.
Gordon Edes covers the Red Sox for ESPNBoston.com. Follow him on Twitter.