The Cubs will try to play Soler in RF in 2015. Alcantara is better suited to play second base/bench than full time CG. The crew of Ruggiano, Sweeney, Baker and Kalish have no future with the rebuilt Cubs of the future. So the Cubs could dabble to upgrade OF and back up catcher in the off season.
You don't want to block Bryant's promotion to 3B.
Potential Free agent list:
Catchers
Alex Avila (29)
Brayan Pena (34)
Matt Wieters (30)
Left Fielders
Yoenis Cespedes (30)
Alejandro De Aza (32)
Gerardo Parra (29)
Center Fielders
Alejandro De Aza (32)
Dexter Fowler (30)
Tony Gwynn Jr. (33)
Austin Jackson (29)
Gerardo Parra (29)
Drew Stubbs (31)
Right Fielders
Jason Heyward (26)
Gerardo Parra (29)
Strike through players are too old or too expensive for stop gap players. However, those still on the list could be "too expensive" for the Cubs as well, as there will be interest in players like Heywood, Parra, Jackson just on age alone. Cespedes is on the list, and he would be expensive catch, but if the Cubs are going to make one "big" free agent signing this off-season, it would be more likely an every day player than breaking the bank for a big name pitcher like Lester.