The Toronto Blue Jays have relied on an unheralded weapon to climb back into the American League playoff race -- their bullpen.

Before tonight's game, Toronto's relievers had recorded 11 of the team's past 22 wins, helping the Blue Jays become the hottest team in baseball and lifting them into playoff contention.

Just two months ago, Toronto trailed then-division leader Boston by nine games. After a 32-12 stint, the Blue Jays were just five games behind the first-place Yankees heading into a three-game series starting tonight in New York.

"The success of our bullpen is one of the main reasons we're challenging for the playoffs right now," Manager Jim Fregosi said. "It's been a rock."

It has had to be since the team's starting pitchers have been inconsistent.

The rotation was a combined 42-34 with a 5.07 earned run average, sixth in the AL but far below league-leading New York's 4.21.

After a rough start, the bullpen was 17-14 with a 4.39 ERA, fourth-lowest among AL teams. Last year, Toronto's relievers were 21-23, and their 4.68 ERA was 11th best. As recently as June 1, the ERA for the Blue Jays' bullpen was 5.18.

What is surprising is that the bullpen was a work in progress in the winter and early this season. Robert Person was the team's closer and untested players Tom Davey and Peter Munro were sixth- and seventh-inning regulars.

Paul Quantrill returned on June 4 from an offseason snowmobile accident and, along with left-hander Graeme Lloyd, has given Fregosi a dependable lefty-righty combination for the seventh and eighth innings.

Quantrill was 1-1 with a 2.70 ERA. Lloyd was 5-3 with three saves and had a 3.10 ERA.

Roy Halladay, meantime, was 8-4 in a combination relief and spot starting role, and John Frascatore, acquired June 13 from Arizona, was 6-0.

The biggest factor, though, may be a 24-year-old rookie.

Armed with a 101-mph fastball, Billy Koch was promoted to Toronto on May 5. A converted starter, he had a 2.41 earned run average and 21 saves, putting him within striking distance of Todd Worrell's 1986 record with St. Louis of 36 saves by a rookie.

"I've gotten myself in a few pickles, but you know with the players on this team that you're going to get solid defense and all the help offensively you could ask for," Koch said.

General Manager Gord Ash gets much of the credit for patching together the bullpen and a series of other moves to get the team in contention for its first playoff berth since winning the World Series in 1993.

Ash's best move may have been acquiring David Wells, Homer Bush and Lloyd from the Yankees in February for Roger Clemens. While Clemens has yet to show the form that helped him win the past two Cy Young Awards with the Blue Jays, Wells is 11-6 and Bush is batting .307 as the everyday second baseman.

With the Yankees, Clemens is 9-4 with a 4.78 ERA.

Of course, the next two months won't be easy. Toronto plays 33 of its last 55 games on the road and will face division leaders New York, Cleveland and Texas a combined 20 times.

"We've done well in the past few months," Fregosi said. "Now we'll see if we can play with the big boys when it really counts."