CLEVELAND -- Detroit's dynamic pitching duo turned into an even tougher trio Friday, making the Tigers' postseason chances potentially three times as strong.

The Tigers built their post atop the American League Central behind the devastating pitching of Justin Verlander and Edwin Jackson. With a chance to bolster its playoff chances at Friday's non-waiver Trade Deadline, Detroit played to its strength and made it better, acquiring Jarrod Washburn from Seattle in exchange for fellow left-handers Luke French and Mauricio Robles.

The move gives the Tigers three of the seven lowest ERAs among American League starters for the stretch run, something no other team can claim. It also gives them the potential for a postseason rotation few teams can match.

"I think that's something that'll be fun to watch," Verlander said of the trio. "You never know what's going to happen, but it's fun to think about it."

It marks the third time in four years that the Tigers have pulled off a trade around the July 31 non-waiver Trade Deadline, but this is by far the biggest of those deals. While Roy Halladay and Cliff Lee dominated the headlines for most of the week, Washburn's July numbers arguably ranked him as the hottest pitcher who was available.

"Jarrod Washburn is pitching, I think, probably as well as anybody in the league right now," team president/general manager Dave Dombrowski said.

The 34-year-old Washburn will be eligible for free agency at the end of the year. However, his contribution to the Mariners made him worth the rental price for the Tigers. Washburn's 2.64 ERA ranked third-lowest in the American League to go with an 8-6 record, while allowing just 109 hits over 133 innings with 33 walks and 79 strikeouts.

Within those stats, however, is a July tear that raised appeal to a lot of teams on the market. Washburn has allowed just three runs on 20 hits in 36 2/3 innings over his past five starts, all of them Mariners victories.

If the Tigers needed any more evidence how much of an impact Washburn can make, they saw it when he baffled the Tigers on July 23 at Comerica Park. Washburn pitched seven scoreless innings against Detroit that day, allowing just two hits in his fourth consecutive victory, before he allowed a run and scattered five hits in seven innings against the Blue Jays in his most recent start on Tuesday.

Washburn helped Seattle creep into the thick of the AL West race until it fell back over the past week, turning the Mariners into sellers. His arrival in Detroit not only bolsters the Tigers' chances to break out of the three-team scrum in the AL Central, but also helps them shape up as a competitive foe in a postseason series.

Washburn will make his Tigers debut Tuesday against the Orioles, in between Verlander and Jackson.

"It is sad to be leaving," Washburn told reporters in Texas, where the Mariners face the Rangers this weekend. "But at the same time, I'm very happy and excited to be going to a team that's in first place. I am happy to be joining them, try to help them get to the playoffs and hopefully win another ring."

The Mariners were reported to have interest in signing Washburn to a contract extension. Washburn is represented by agent Scott Boras, who's known for preferring that his clients enter free agency rather than re-sign in midseason. Given that, this very much reflects a short-term deal for the Tigers, but one they were willing to make given the situation.

"I don't know what will happen beyond this year," Dombrowski said. "I do know who his representative is, so I know it's not going to be something that we [have] conversations in the middle of the season. We'll see what happens beyond this year, but we're trying to win."

The 23-year-old French cracked the Tigers' rotation last month following steady success at Triple-A Toledo. He went 1-2 with a 3.38 ERA in five starts and two relief appearances for the Tigers, but lasted six innings in only one of his five starts. He quickly ascended the Tigers' development ladder after being selected in the eighth round of the 2004 First-Year Player Draft.

"He really has come on tremendously," Dombrowski said, "and I told him I tip my cap to him, because he continued to get better and better. He's really pitched well. But it just came to the point that we needed more experience in our rotation."

Robles, who turned 20 years old in March, has split this season between Class A West Michigan and Lakeland, going 8-6 with a 4.24 ERA and 111 strikeouts over 91 1/3 innings. He allowed just 79 hits in that span.

He wasn't among the Tigers' top 10 prospects at the start of the year, but he had made enough of an impression to earn notice. He was the prospect the Mariners targeted when trade talks picked up a week ago, Dombrowski said.

"He has an above-average arm," Dombrowski said. "He's striking out more than one per inning, so he's got a real good arm. His secondary stuff still needs to be developed, and that's why he's in A-ball. At times, he shows you a very good breaking ball, but it's still inconsistent."

This is the third time in four years that the Tigers have pulled off a deal within 48 hours of the Deadline. Detroit swapped Ivan Rodriguez for Kyle Farnsworth last year, and acquired Sean Casey at the 2006 Deadline in exchange for Minor League pitcher Brian Rogers.

Casey helped the Tigers to the World Series after speculation that year centered on Alfonso Soriano. The Tigers are hoping Washburn can help them get back.

"Pitching and defense, that's what wins baseball games, especially in the postseason," Verlander said.