OAKLAND, Calif. -- Oakland backup catcher Landon Powell had another big day then prepared himself for a return to the Athletics' bench.
Making a rare start in place of starter Kurt Suzuki, Powell threw out a baserunner in the first inning then hit his first career grand slam in the second to help Oakland beat the Kansas City Royals 10-4 Wednesday.
The four RBIs were a career-high for the A's rookie, who has driven in 27 runs over his first 36 games in the majors. Yet when Oakland hosts Seattle in a four-game series beginning Thursday, the 27-year-old Powell is almost certain to go back to his customary spot on the bench.
"It's not frustrating, I understand it's early in my career," Powell said. "We've got a great starting catcher who works hard and is one of the better players in the game. As a player you always want to play more."
Suzuki leads the A's in RBIs and is second on the team with 11 home runs. He earned a day off from manager Bob Geren then watched his understudy put a hurting on the reeling Royals.
It's something Oakland is getting accustomed to seeing from Powell. He has thrown out seven of 15 baserunners trying to steal and is batting .393 with runners in scoring position.
Powell's 27 RBIs are also the second-most in franchise history by a player in his first 36 games. Ben Grieve drove in 30 in his first 36 games, though it was spread out over two seasons.
"A backup catcher's job is very difficult," Oakland manager Bob Geren said. "Weaknesses usually stand out and strengths are usually not even as strong as they could be every day. He deserves a lot of credit for what he's done in the role he's done it."
Mike Jacobs homered for the Royals, who lost two of three against Oakland without manager Trey Hillman. Hillman, who left on Monday to be with his family following the death of his father-in-law, is expected to rejoin the team Friday in Kansas City.
"It was one of those series that we were fortunate to get away with one win," interim manager John Gibbons said. "They make you throw strikes that's the way they've always been here. If you don't do that you are under the gun the whole game."
Cahill (8-12) gave up three runs and six hits in five innings. The A's right-hander had not won consecutive starts since mid-June and is only 3-7 in his last 13 starts.
He ran into trouble only once, in the third when Jacobs homered and David DeJesus and Alberto Callaspo added RBIs. Following Jacobs' solo home run, Cahill retired seven of the next nine to end his afternoon.
Brad Kilby gave up one hit in two innings during his major league debut while Jerry Blevins and former Oakland starter Dana Eveland pitched the final two innings to complete the nine-hitter for Oakland.
Bannister, who lives 30 minutes east of the Coliseum during the offseason, gave up three runs in the first inning then left after getting Cliff Pennington to pop out to second base leading off the second. Gibbons and assistant trainer Frank Kyte met with Bannister on the mound briefly before Gibbons signaled to the bullpen for Yabuta, ending the day for Bannister (7-12) after only 32 pitches.
"I went out there and didn't have much at all today," Bannister said. "I've been battling this for a month now and it's extreme fatigue and just soreness in the back and my shoulder. It's not sharp pain so I don't think it's anything serious."
After Bannister left, the A's batted around against Yabuta to break the game open. Rajai Davis' sacrifice fly drove in Eric Patterson, then Powell followed with his first career grand slam three batters later to make it 8-0.
Kansas City came back with three runs off Cahill in the third but Oakland scored twice in the bottom of the inning, one when Davis was hit by a pitch and the other on a double-play groundout by Jack Cust.
Sweeney had a two-run single in the first then singled and scored in the second.
The Royals, losers of 10 of 14, were in danger of being held to three runs or less for the 20th time since the All-Star break until scoring a run off Eveland in the ninth.
Before the game Oakland reinstated INF Bobby Crosby from the 15-day disabled list. ... The A's claimed RHP John Meloan off waivers from the Pittsburgh Pirates and optioned him to Triple-A Sacramento. ... Royals DH Jose Guillen went 0-for-2 in his first start since coming off the DL but left the game after five innings due to soreness in his right hamstring.