The front office will look awful if they don't try to resign Lester. Lester has been talking about the hometown discount a great deal. He seems convinced that Boston is the best place for his family, he has been talking about how he really doesn't want to have to get to know a whole new clubhouse.
The best free agent options seem to have been dwindling. Scherzer is on the market for now, but he'll probably cost twice as much as Lester if he doesn't re-sign. Bailey is off the board. Masterson is no replacement. Any trade for a pitcher in Lester's class would cost Bradley and Owens, if not Xander.
Lester pitched to a 0.59 ERA in the World Series, and seems like he will only improve with Salty away from the mound. Losing Ellsbury hurt, but losing Lester would turn the club upside down.