Jason Giambi has a simple theory when it comes to knuckleballers.
"Swing hard and hope you hit it," he said.
The solo shot came off knuckleballer Steve Sparks (9-8) and gave the A's a 2-1 lead in the fifth inning.
"He's a great hitter," Sparks said. "It was low, on a 3-2 pitch, and he went down and got it. There's not much you can do about that."
Despite the four-game skid, the A's still have won 17 of their last 23 games and they maintain a narrow lead over the Boston Red Sox for the AL wild card.
Barry Zito (10-8), who has won seven of his last nine decisions, gave up one run on four hits in six innings. He walked three and struck out seven.
Sparks, who threw a complete game on Monday at Seattle in a 4-1 Tigers' victory, gave up five runs and eight hits in 6 1/3 innings.
The A's went up 1-0 in the second inning on F.P. Santangelo's RBI single.
The Tigers tied it in the fifth on Roger Cedeno's single to right, scoring Juan Encarnacion, who doubled. The run stopped Zito's scoreless streak at the Coliseum at 28 1/3 innings.
After Giambi's home run, Miguel Tejada had an RBI single in the sixth, Terrence Long had an RBI single in the seventh and Jeremy Giambi hit a run-scoring single in the eighth for Oakland.
Escobar (6-5) struck out eight and walked two in his second career shutout. It was his first complete game since that shutout, on June 21, 2000, against Detroit.
The Orioles got only two runners as far as second base, none after the second inning. Escobar ended it by striking out Jeff Conine on a pitch clocked at 98 mph.
It was the Blue Jays' second shutout against Baltimore in as many nights.
Minnesota 7, Kansas City 1--Joe Mays scattered five hits over 8 2/3 innings and broke a personal five-game losing streak in the win at Kansas City.
Mays (13-12) walked two and struck out seven, and lost his shutout on Mark Quinn's two-out RBI single in the ninth.
Cristian Guzman had three hits and two RBIs for the Twins.
The Royals, who have lost five in a row and nine of 12, dropped to 26-38 in Kauffman Stadium, the worst home record in the major leagues.
Tampa Bay 8, Chicago 4--Greg Vaughn hit two RBI doubles for the Devil Rays at St. Petersburg, Fla.
The game was delayed 24 minutes in the bottom of the first inning when lightning struck near Tropicana Field and knocked out a bank of lights.
The Devil Rays surpassed the one-million mark in home attendance with Saturday's crowd of 26,597. Montreal is the only major league team to fail to reach the mark this season.