OAKLAND -- Bartolo Colon failed to reach the sixth inning for a fourth straight start and the A's fell back into second place in the American League West.
With 24 games left to play, the Texas Rangers regained a one-game lead in the division by topping Colon and the A's 5-1 at the O.co Coliseum on Tuesday.
After going 8-1 with a 1.75 ERA over 11 starts in June and July, Colon (14-6) is now 0-3 with a 6.48 ERA since Aug. 1.
But he allowed only one earned run on eight hits against the Rangers on Tuesday.
Manager Bob Melvin said he pulled the 40-year-old after five innings because he didn't think it was wise to push him further after 80-plus pitches. Colon was also hit in the hand by a hard ground ball.
"It's not like they knocked him around," Melvin said. "Got a few bloop hits and they hit the one home run."
Colon ran into trouble in the fifth after he allowed a pair of ground balls to get away from him, opening the door to a three-run inning.
With the score tied 1-1, Craig Gentry hit a high chopper that deflected off the heel of Colon's glove as he reached up over his cap to snag it. Colon was charged with an error and Gentry scored on Jurickson Profar's double off the right-field wall, giving the Rangers a 2-1 lead.
"I believe that one play made the difference," Colon said through translator Ariel Prieto.
Ian Kinsler followed by smacking a hard ground ball to the mound that was too sharp for Colon to handle. The ball hit Colon's glove and his bare right hand and Kinsler legged out an infield single. Profar moved over to third on the hit and then scored on a ground out by Adrian Beltre. A.J. Pierzynski stretched the lead to 4-1 by driving in Kinsler with a single.
Josh Donaldson might have made the catch of the year in the sixth inning when he fell over the tarp next to the stands along the third-base line to snag a foul ball off the bat of David Murphy.
"If I get that opportunity, I'm willing to throw by body over [the tarp] to make that," Donaldson said.
Michael Choice, the A's first-round draft pick in 2010, picked up his first big-league hit with a slow-rolling infield single to pitcher Martin Perez in the fifth.
"It's going to end up looking like a line drive in the box score," Melvin said. "You get your first hit, doesn't matter how you get it."
Choice also ended the Rangers' fifth-inning rally with a sliding catch in right.
The A's jumped on the board first after Coco Crisp led off the game with a double into the left-field corner and scored on a sacrifice fly to right from Jed Lowrie. Crisp served as the team's DH after leaving Monday's game with a shin contusion.
Mitch Moreland tied the game in the fourth by hitting his 22nd home run of the season on a 1-1 change-up from Colon.
The Rangers added a fifth run in the eighth off Alex Rios' 14th home run. Perez (9-3) picked up the win, giving up one run over seven innings.
Notes: The A's expanded their bullpen to 11 pitchers on Tuesday, recalling right-handers Pat Neshek and Evan Scribner from Triple-A Sacramento while bringing up left-hander Tommy Milone from Class-A Stockton. "It certainly gives you added depth," Melvin said. ... A's slugger Brandon Moss earned American League Player of the Week honors on Tuesday after batting .364 with eight home runs and 11 RBIs during the week that ended on Sept.1.