OAKLAND, Calif. -- Justin Duchscherer can handle a line drive off his wrist. It's the command issues he struggled with that caused Oakland's right-hander the most frustration.
"I had trouble gripping the ball," said Duchscherer, who struck out three while winning for only the second time in his last five starts.
"The balls are rubbed up with a mud and as the innings kept going that mud stuck on my hand and (the ball) started slipping. I'm a little disappointed in myself because I lost my composure because of it. Those two things compounded got me in a little bit of trouble with my command."
Duchscherer (5-4) also survived being hit just above his left wrist by Carlos Guillen's line drive in the sixth inning.
Duchscherer, who had hip surgery last year and spent 17 days on the disabled list in April with a strained right biceps, initially thought he broke his arm on the play. He remained in the game to help lead Oakland to its fourth straight win.
Travis Buck hit his second home run of the season and Daric Barton matched his career high with three hits for the A's. It's the fifth time this season Oakland has swept a three-game series after having only three three-game sweeps in all of 2007.
"Lot of real positive things," A's manager Bob Geren said. "The home runs, the big two-out hits, the big inning and strong pitching ... that's just a great formula to win. It was a real good day for us."
Tigers starter Nate Robertson (3-6) gave up five runs and eight hits in 6 1/3 innings. The left-hander had won his previous two decisions but remained winless in five starts in Oakland.
The Tigers haven't fared much better away from Detroit. They finished their nine-game road trip with a 3-6 record and return Friday for the start of a 10-game homestand.
Alan Embree, Brad Ziegler and Kiko Calero finished the four-hitter for Oakland while handing Detroit its fourth loss in five games. The Tigers dropped a season-high 11 games under .500 at 24-35.
"It looked like we were swinging our bats under water," Detroit manager Jim Leyland said. "I am very disappointed in our offense. Our offense stunk, basically. I'm befuddled about it. I've said that all year."
Detroit's frustration showed in the fourth when Magglio Ordonez got into a brief exchange with home plate umpire Angel Hernandez after being called out on strikes for the third out. At one point Hernandez pointed at Ordonez just before the Detroit slugger slammed his helmet to the ground and flung his bat to the side.
The day didn't get any better for the Tigers.
Shortstop Ramon Santiago separated his left shoulder in the seventh after diving at Rob Bowen's RBI single to center. Santiago rolled around on the ground and winced in pain when a team trainer tried to touch his shoulder and was later taken to the clubhouse.
Santiago was scheduled to undergo X-rays on Thursday and the Tigers expect to place the 28-year-old infielder on the disabled list shortly thereafter.
Bobby Crosby's double in the fifth sailed over the head of left fielder Marcus Thames, allowing Jack Hannahan and Jack Cust to score to make it 3-0.
Duchscherer retired nine straight and had faced only one over the minimum through five innings before running into trouble with one out in the sixth. He issued back-to-back walks to Ryan Raburn and Curtis Granderson before Guillen lined a 1-0 pitch straight back at the mound, sending the ball caroming off Duchscherer's left arm and into center field.
Duchscherer knelt on the ground and grabbed his arm as Raburn scored but stayed in the game after being checked out by Oakland's coaching staff and a trainer. He walked the next batter to load the bases then hit Ordonez to force in another run but escaped the jam by getting Jeff Larish to ground into a double play.
"When it hit me it hurt pretty good," Duchscherer said. "My first thought was, 'Oh I hope I didn't break my arm' because it hit right on the bone on the wrist. But it didn't hurt so bad where I couldn't keep pitching."
Buck, whose double-play grounder in the fourth scored the A's first run, homered to begin the sixth for a 4-2 lead.
Carlos Gonzalez drove in three runs with a bases-loaded double in the six-run seventh.
A's 3B Eric Chavez was given the day off to rest his legs after homering in Tuesday's win over the Tigers. Chavez missed the first 53 games of the season recovering from offseason back surgery.