Now sitting in second place, the A's will try to regain the advantage with a series at home against a woeful Houston Astros team they've dominated. A healthier Colon might have a good chance to help Tuesday night, given his recent performances against them.
The A's had a six-game lead in the division July 29 but frittered away the last of that edge with a 6-5 loss in Cincinnati on Wednesday. Colon (14-4, 2.75 ERA) gave up five runs - the most he's allowed since May - and seven hits with three walks in a season-low 2 2-3 innings.
Colon was 3-0 with a 1.57 ERA in his previous five outings. He said after the game, in which he threw only 37 of his 67 pitches for strikes, that he had been dealing with a stomach virus.
"It is no excuse," he said through interpreter Ariel Prieto. "I wasn't throwing strikes like I did before the All-Star game."
Oakland (67-50) kept its deficit behind red-hot Texas at one game by winning the last two days in Toronto after dropping seven of nine. Alberto Callaspo helped give his team a 5-1 victory Monday by hitting his second tiebreaking two-run double in as many days.
"Hopefully this is a sign of things to come for us," first baseman Brandon Moss told the team's website.
The A's will try to keep heading in the right direction against a major league-worst Astros team that has lost 31 of 38. Houston (37-80) was no-hit through 7 1-3 innings in a 2-1 loss to Texas on Monday, its season high-tying sixth in a row.
Carlos Corporan broke up Yu Darvish's bid at history with a solo homer, but Houston didn't get another runner on base.
Oakland is 16-2 all-time against the Astros and 11-1 this season, hitting 18 homers and averaging 6.7 runs. The A's have never lost in six home games versus Houston, including three from April 15-17.
Colon is 3-0 with a 1.89 ERA in three starts against the Astros this year without walking a batter. The right-hander has a chance to join Detroit's Max Scherzer as the majors' only pitchers to reach the 15-win mark.
He'll pitch opposite a struggling Jordan Lyles (4-6, 5.40). The right-hander is 0-3 with an 11.17 ERA in his last four starts after losing to Boston last Tuesday, getting charged with eight runs over 4 2-3 innings in a 15-10 defeat.
"My bad outings have been bad, real bad," Lyles said. "I'm just trying to stay away from them."
Lyles will face Oakland for the first time, but Chris Young has plenty of experience against him, going 5 for 9 with a home run and a double.
The A's are hoping Coco Crisp can return after sitting out Monday with an injured wrist. He's batting a team-best .386 with four homers and 10 RBIs in 11 games versus Houston this season.
Jason Castro, riding a 10-game hit streak, is batting a team-best .375 with three homers this season against Oakland. Castro and Jose Altuve missed Monday's game because of nagging injuries, but neither is considered serious.