With a thin rotation behind Halladay and a largely unheralded lineup, Toronto's early surge has been somewhat surprising, but the Blue Jays have benefited from a soft April schedule.

The Blue Jays (15-9) have yet to face Boston, Tampa Bay or the New York Yankees - the presumptive top contenders in the AL East - and have played 18 games against the weaker AL Central.

Toronto went 24-12 against the Central last year compared to 37-35 versus the East - a record boosted by its 12-6 mark against Baltimore.

"Even last year, any time we went in to play Baltimore, and we played them a lot, we really had to go to beat them," Toronto manager Cito Gaston told his team's official Web site. "And they were considered a last-place team."

The Blue Jays cooled off this week as they dropped three of four at Kansas City, losing the final two. With starting pitchers Ricky Romero, Dustin McGowan, Shaun Marcum and Jesse Litsch on the disabled list, Brian Tallet and Brian Burres were roughed up to close out the trip.

Toronto will have a better pitcher on the mound Friday night. Coming off a 20-win season, Halladay (4-1, 3.75 ERA) is off to another strong start, and facing the Orioles usually only helps the right-hander. He's 8-0 with a 2.64 ERA in his last 10 starts against Baltimore.

"It's always great when Doc is on the mound," center fielder Vernon Wells said. "Obviously, the start of the series, and we get to play teams within our division. It'll be great to see No. 32 back on the mound."

That's especially true after Burres and Bryan Bullington combined to allow eight runs and four walks in the first five innings of Thursday's 8-6 loss. Both were sent to the minors after the game.

They weren't helped by Toronto hitting into six double plays.

"I always talk about how much we win as a team," Gaston said. "We sure lost as a team today."

The Orioles (9-13) have been losing frequently, going 3-11 since a 6-2 start. Their woeful pitching staff has allowed 6.7 runs per game and an opponents' batting average of .300 over that span.

Mark Hendrickson (1-3, 5.40) is among the Baltimore pitchers who have struggled, as he's compiled a 6.92 ERA in losing his last three starts. The veteran left-hander has given up 20 hits - six home runs - along with eight walks in 13 innings of those games.

Baltimore is opening a five-game trip with three in Toronto after closing its homestand with three straight losses. The Orioles fell 3-2 to Los Angeles on Wednesday, completing a two-game sweep.

"We've had a lot of opportunities to win some games," manager Dave Trembley told the Orioles' official Web site. "We showed a lot of fight. We had leads. ... It's frustrating, but there's not much you can do about it now. You've got to grind it out."

Nick Markakis extended his hitting streak to 16 games Wednesday but the Orioles fell to 0-9 when scoring four runs or fewer.