OAKLAND -- A's outfielder Josh Willingham knows that he's been on a hot streak at the plate. He just can't explain why.

Entering Sunday's game against Toronto, Willingham had blasted nine home runs in his previous 21 games. And he had hit 11 home runs since the All-Star break, tied for most in the American League.

"It seems like when I'm getting a pitch to hit and I hit it hard, some of them have been leaving the park," Willingham said. "I think that's the difference. A lot of times you hit singles and doubles. I've kind of been on a home run streak, but I can't explain it."

Willingham entered the game with a team-best 22 home runs, four off his career high of 26 set in 2006 with Florida. He had a team-high 73 RBIs, 16 off his career-high of 89 set in 2009 with the Marlins.

"Between he and [Hideki] Matsui, they're our stabilizing forces in the middle of the lineup that take a little pressure off everybody," A's manager Bob Melvin said. "With the offensive struggles we had in the first half, to come out in the second half and completely turn the tables, it's led by those two.

"And certainly recently, Willingham's homers have not only been frequent, but they've been important. Whether it's a first-inning homer, an early-game homer that puts you ahead, or like last night when he pads on a lead a little bit. He's not hitting them when you're up 10-1 or down 10-1. He's hitting them when it counts."

In the A's 5-1 win over Toronto on Saturday night, Willingham hit a pinch-hit, two-run homer in the eighth inning. He also hit a two-run shot on Friday night in the A's 2-0 win over the Blue Jays.

Allen making the most of latest opportunity

OAKLAND -- A's first baseman Brandon Allen has played for four teams across two organizations this year, but he's starting to enjoy what's been a roller-coaster ride of a season.

Allen entered Sunday's game against Toronto hitting .407 with two doubles and two triples after starting eight straight games since being called up from Triple-A Sacramento on Aug. 13. He's had a pair of three-hit games during that stretch.

"It's been fun so far," Allen said of his hot stretch. "It's just baseball. You can be up, you can be down. I'm happy right now, thankful for things that I've gotten so far. I just have to keep going."

The A's acquired the 6-foot-2, 235-pound Allen on July 31 from Arizona along with pitcher Jordan Norberto for pitcher Brad Ziegler. This is his second career midseason trade. The White Sox traded him to Arizona on July 7, 2009.

A's manager Bob Melvin said that it didn't take long for Allen to impress him with his performance in the field and at the plate.

"The small sample's been pretty good, across the board, too," Melvin said. "The at-bats, the at-bats against left-handers, his defense, his base running. He's a good athlete, and you don't see that that often in your first baseman, to be that good an athlete.

"There's going to be periods when you're not going to swing the bat well, but you bring your glove out there and you make everybody in the infield that much better by picking balls and doing such over at first base. He runs the bases very well. He's been very impressive to this point."

Allen came to the A's with a reputation for being a power hitter, but no one expected him to hit for such a high average. In 65 career games with Arizona, he hit eight home runs and batted .213. This year he hit three home runs in 11 games with Arizona, but has yet to hit his first long ball for Oakland.

"You see the power in batting practice, and I think he's a couple feet away from three home runs already," Melvin said. "At this park, especially at night, it can be difficult to go the other way like he did last night, hit the ball off the top of the wall. The home run numbers will come. It's nice to see the consistent at-bats that we're getting out of him."

As for his defense, Allen said that that's a product of years of hard work.

"It took me a while to get a grasp of it," Allen said. "The past few years I really bore down on it. I'm feeling more comfortable. Once you get in that groove, things look smooth. They're really not, but you've got to keep practicing just to stay a decent defensive player."

Allen said that he had "mixed emotions" when he heard that he had been traded to the A's. He also said that he wasn't aware of the A's history of giving young players opportunities at the big league level.

"All in all I'm happy about it," Allen said. "They called me up, gave me an opportunity, and thankfully enough I've been playing really well."

Worth noting

• Right-handed relief pitcher Michael Wuertz, who's on the 15-day disabled list with tendinitis in his right thumb, threw a bullpen session on Sunday and moved closer to a rehab assignment.

"I'm sure there's at least another bullpen involved until we send him out," A's manager Bob Melvin said.

• After a day off on Monday, the A's begin a 10-game road trip on Tuesday night against the Yankees. They play three games in New York, three in Boston and four in Cleveland. On their last road trip they won two out of three series, snapping a string of 12 straight winless road series (0-9-3).

"To win those two -- especially in Tampa and Toronto -- which can be tough places to play, it was a good feeling," A's manager Bob Melvin said. "Hopefully the fact that we did win some games on the road adds to our confidence going on the road."