Updated

C.J. Wilson got together with Los Angeles manager Mike Scioscia and pitching coach Mike Butcher recently to brainstorm ways for him to snap out of a recent slump.

The first session didn't seem to take. Wilson matched his second-shortest outing of the season and the Angels fell to the Oakland Athletics 10-4 on Tuesday night, his first loss with Oakland in 18 appearances.

"It's not like there was a to-do list," Wilson said of the meeting. "Take out the garbage, call your grandma, these kind of things. I gave up a home run on an 0-2 pitch, a first-pitch changeup triple, an infield hit on a curveball. Sometimes there are going to be things that just don't work out even if you don't have a good plan."

Wilson (9-8) remained winless since June 26, a span of nine starts. He never allowed more than five runs in his first 19 starts and has given up six or more in three of his last six starts.

Wilson gave up six runs — three earned — and nine hits in five innings. He walked five and struck out four.

"It took C.J. a lot of work to get through the five innings," Angels manager Mike Scioscia said. "The miscue didn't help at third base but still, his ball-strike ratio and his ability to repeat pitches just wasn't consistent."

Erick Aybar hit a two-run homer, Mike Trout hit a home run and Maicer Izturis drove in a run for the Angels, who lost for the fifth time in seven games.

Trout became the fifth major leaguer to hit a home run on his 21st birthday, joining Ted Williams, Frank Robinson, Alex Rodriguez and Jason Heyward. He is the youngest ever to produce a 20-homer, 30-stolen base season.

"Right now it means nothing," Trout said. "That's the kind of stuff that pops up at the end of the season."

The A's parlayed a fielding error by third baseman Alberto Callaspo into four runs — one earned — in the third.

Izturis singled home a run, unearned as a result of second baseman Weeks' throwing error, in the seventh to end former Angel Bartolo Colon's scoreless streak at a career-high 22 1-3 innings.

Notes: Angels OF Torii Hunter has hit safely in 15 of his last 16 games. ... RHP Zack Greinke (0-1, 5.14) makes the start for the Angels on Wednesday. Greinke is 2-0 in seven games in Oakland. ... RHP Dan Straily (0-0, 1.50) makes the start, the second of his career, for the A's. ... Wilson had not allowed a home run in his first 17 appearances (four starts) in Oakland. ... The Angels' bullpen has allowed 27 runs in 24 1-3 innings through nine games of the road trip.