Making certain assumptions about health and starters...

Starters (8):
CF - Pagan
2B - Sanchez
3B - Sandoval
C - Posey
LF - Cabrera
1B - Huff
RF - Schierholtz
SS - Crawford

Backup Catchers (1):
C - Stewart
C - Whiteside
C - Sanchez

Non-Catcher Backups (4):
1B/LF - Belt
1B/LF/2B? - Pill
IF/LF - Burriss
2B/SS/3B - Fontenot
2B/SS/3B - Theriot
3B/2B - Gillaspie

Only 1 of Stewart, Whiteside, and H. Sanchez will stay. There will likely be at least 2 backup OF and 1 1B. So Belt, Pill, and Burriss are battling for 2 spots. That leaves Burriss, Fontenot, Theriot, and Gillaspie battling for the last 2 spots.

My guess is that Belt (optioned) and Gillaspie (may have to be released?) will not be on the opening day roster.