According to Jayson Stark, he's going along with the thought that 3B1 is Chris Johnson's/Geoff Blum's to lose. However, should both of them lose it, Stark is tossing out some more possible names:
Juan Uribe (Giants) - 30-year old career .253/.295/.423 and K:BB ratio is about 3:1.
Jose Bautista (Blue Jays) - 28, .239/.324/.398 last year for the Pirates
Jeff Baker (Rockies) - 27, utility infielder, hit .268/.322/.468 in 299 ABs last year.