The blockbuster trade sending Roy Halladay to Philadelphia and Cliff Lee to Seattle could be completed Wednesday, and it's become a four-team swap that involves Toronto shipping a prospect to Oakland.

The Blue Jays would send Halladay and $6 million to the Phillies for three minor leaguers: catcher Travis d'Arnaud, right-hander Kyle Drabek and outfielder Michael Taylor.

Philadelphia would also deal Lee to the Mariners for a trio of prospects: right-hander Phillippe Aumont, outfielder Tyson Gillies and right-hander Juan Ramirez.

Toronto would then trade Taylor to the Athletics for third baseman Brett Wallace, obtained by Oakland last July from St. Louis in the deal for outfielder Matt Holliday.

Halladay would receive a $60 million, three-year contract extension through 2013 with the Phillies, a deal that would include a 2014 option.

Details of the nine players involved in the swap of Cy Young Award winners, first reported by ESPN.com and prospectinsider.com, were confirmed by several baseball officials familiar with the talks who spoke on condition of anonymity because the trade was not yet final. Teams were still reviewing medical records and going through the final details.

New Toronto general manager Alex Anthopoulos moved quickly to deal Halladay, who will make $15.75 million next year and had been eligible for free agency after the season. The deal fell into place at about the same time Boston _ which also had been interested _ reached a preliminary agreement with free-agent pitcher John Lackey on a five-year contract worth $80 million to $87.5 million.

"Roy Halladay is one of the better pitchers in baseball," Mets general manager Omar Minaya said. "I wish Alex would have traded him to the American League."

Lee, who had both of the Phillies' World Series wins, also is eligible for free agency after next season, when he will make $9 million. He is not getting an extension as part of the trade.

His agent, Darek Braunecker, said he had just begun discussions on a contract extension with Philadelphia.

"At no point did we make any financial demands or price him out of the market, so to speak," Braunecker said. "We were in the very, very preliminary stages of negotiations."

In a deal that was completed, the Chicago White Sox acquired leadoff man and left fielder Juan Pierre and $10.5 million from the Los Angeles Dodgers for two players to be named.

"They already have a good team in place," Pierre said. "They've been accustomed to winning over the last four or five years. I'm looking forward to getting out there on the field on a regular basis."

The 32-year-old hit .308 with 30 stolen bases, 57 runs and a .365 on-base percentage in 145 games with the Dodgers last year, getting steady playing time when Manny Ramirez was suspended 50 games for violating baseball's drug policy. Once Ramirez returned, Pierre became a reserve again.

Halladay, the 2003 AL Cy Young Award winner, had a 2.78 ERA in 2008 and a 2.79 ERA last season in the American League, and will be expected to allow even fewer runs in the NL, where pitchers bat.

His arrival figures to strengthen the Phillies to the detriment of their NL East rivals, but weaken challenges to the World Series champion Yankees and Red Sox in the AL East.

In the AL West, Lee joins a Seattle rotation that already includes young ace Felix Hernandez. The Mariners added speedy Chone Figgins to their lineup from the division rival Los Angeles Angels and still are seeking power to replace third baseman Adrian Beltre.

"We've had a lot of discussions going on, a lot of balls we've been juggling," general manager Jack Zduriencik said.

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AP Baseball Writer Janie McCauley, AP Sports Writers Gregg Bell, Rob Maaddi and Andrew Seligman and AP freelance writer Ian Harrison contributed to this report.