Report: Roy Halladay Traded to Phillies in Three-Team Blockbuster The biggest name on the trade market may be on the move.

Roy Halladay has been traded to the Phillies, according to Jon Heyman of SI.com.

The report says that the Phillies, Blue Jays and Mariners agreed in principle to a three-team blockbuster, in which the Phillies will send Cliff Lee to the Mariners, while Seattle will send a group of prospects to Toronto.

Earlier on Monday, The Philadelphia Inquirer reported that Halladay and his agent checked into a Philadelphia hotel.

The deal would likely be dependent on Halladay signing an extension with the Phillies, as his contract is set to expire after the 2010 season. FoxSports.com's Jon Morosi reports that MLB has not granted the Phillies permission to discuss a contract extension with Halladay, so there may not be an announcement made on Monday.