He has a projected 3.1 WAR, 14th highest among pitchers, which could help him earn a lot of dollars on the market, he's ranked above Cueto, Hamels, Zimmerman, Shields, Samardžija and Wainwright in that category.
Zimmermann is surely someone we'll go after next offseason, but he'll earn $16,5M in 2015 and look for a substantial raise, Lester got only $13M in 2014, and we still couldn't strike a deal.