The Boston Red Sox are the biggest player in talks with the Philadelphia Phillies to acquire Cliff Lee, according to sources.

It remains uncertain how likely Lee is to be traded prior to Wednesday's deadline.

Lee is due about $70 million through 2015 (including a $12.5 million buyout for 2016).

The Red Sox don't want to part with top prospects Xander Bogaerts and Jackie Bradley Jr., but they have a number of other top-flight prospects to use in trades.

Lee has a no-trade clause to 21 teams.