NEW YORK — 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. Lackey’s deal will be announced Wednesday along with outfielder Mike Cameron’s contract in separate news conferences, the Red Sox said late Tuesday night.

“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.