Pirates offseason block

[Cardinals]

I'm looking to mix it up a bit. I'd like to either upgrade 1B or CF. I'm happy with a lot of my team. Following players are available.

Billy Butler
Marlon Byrd
Adron Chambers
Scott Feldman
Frank Francisco
Aubrey Huff
Nick Johnson (ok fine)
David Murphy
Jake Westbrook
Shin-Soo Choo
All prospects

I would listen on Juan Nicasio or Rick Porcello, but I'm not motivated to move them unless it really benefits me. Again, CF/1B is really where I'm looking to improve.