Toronto pitcher Roy Halladay was in Philadelphia on Monday to take a physical for the NL champion Phillies, according to a person with knowledge of the situation - a necessary step before the teams complete a potential blockbuster trade involving the former Cy Young Award winner.

Halladay is the most prized pitcher on the trade market. A six-time All-Star and the 2003 AL Cy Young Award winner, the right-hander went 17-10 with a 2.79 ERA for the Blue Jays last season. He led the majors with four shutouts and nine complete games while throwing 239 innings, second to Detroit's Justin Verlander (240).

Aware they probably couldn't afford to keep Halladay beyond next season, the Blue Jays shopped their ace before the July 31 trade deadline. The Phillies were thought to be involved in talks involving Halladay at that point, but instead they landed lefty Cliff Lee from the Cleveland Indians for four minor leaguers.

SI.com reported Monday that Lee, who also can become a free agent after next season, is expected to be traded to Seattle as part of a three-team deal that would send Halladay to the Phillies. Other outlets indicated it could still be a two-team trade between Toronto and Philadelphia.

The Blue Jays fired general manager J.P. Ricciardi late in the season and replaced him with Alex Anthopoulos. When contacted Monday by the AP, Anthopoulos declined comment.

The Phillies have been busy this offseason, signing free-agent third baseman Placido Polanco to an $18 million, three-year contract. They also signed Brian Schneider to be their backup catcher, and reserve infielder Juan Castro.

Halladay has been one of baseball's best pitchers for years. He owns a 148-76 career record with a 3.43 ERA.