The left-hander had a team-high 16 losses for the Tigers last season when they finished 71-91. For most of this season, Robertson (8-6, 3.61 ERA) has been a steady performer that has helped Detroit (65-32) to the best record in the majors and a comfortable lead in the AL Central.
He’s struggled in July, though, going 0-3 with a 5.82 ERA after winning his previous three decisions.
The losing streak started July 3 against Oakland (61-46), as he gave up five runs and seven hits in seven innings in a 5-3 loss. In his last start on Tuesday, Robertson allowed six runs and nine hits over 6 2-3 innings in a 7-1 loss to the Chicago White Sox.
“I felt pretty good, but every time I missed a pitch, they got it,” Robertson said of his outing against the defending World Series champions. “I made a lot of quality pitches, but they didn’t get themselves out.”
Robertson is 1-2 with a 5.57 ERA in three career starts against the Athletics.
Detroit will face Esteban Loaiza (4-5, 6.38 ERA), who takes the mound for Oakland after earning a win in his last start. He gave up four runs and seven hits with six strikeouts in 5 1-3 innings in a 5-4 win over Baltimore on Tuesday in a game delayed almost 90 minutes by rain.
“You’ve gotta give ‘E-Lo’ a lot of credit,” A’s manager Ken Macha said. “He got us into the sixth, and that was a tremendous lift for us.”
Loaiza surrendered three runs and six hits in six innings, but did not get a decision in a 4-3 win over the Tigers on April 18. He is 11-4 with a 2.67 ERA in 17 starts and two relief appearances against Detroit.
In a series between division leaders, Oakland evened it with a 9-5 victory on Saturday.
“I think the team showed a lot of heart and a lot of character,” Kotsay said. “We didn’t bow our heads going in against a good ballclub.”
Bradley, who has been hot since coming off the disabled list July 12, put the A’s ahead 8-5 with a 436-foot shot to left in the sixth. He is batting .482 (14-for-29) with eight RBIs and six runs in seven games since his return.
Oakland, though, may be without shortstop Bobby Crosby after he left with a sore back. Crosby is hitting .500 (5-for-10) in his career against Robertson.
The loss ended Detroit’s three-game winning streak.
“We’re not going to win every day,” Tigers manager Jim Leyland said.
Designated hitter Dmitri Young was 1-for-4 in his second game back with the Tigers after being on the disabled list since May 22 with a leg injury and personal issues, including treatment for substance abuse at a California rehab center. He went 2-for-4 with two RBIs on Friday.
Tigers shortstop Carlos Guillen is batting .643 (9-for-14) with a home run, a double and two RBIs in his career against Loaiza.