I have read Baggio and sateeh's comments, but I opted to let Zebina go.
Why?
1. I doubt he has the heart to play anyway
2. He doesn't wanna stay, why keep an unhappy player? Let him go somewhere of greener pasture to him
3. Balzaretti has already taken his place I'm sure
4. Provided that Chiellini is injured, Balzaretti can go to the left. I rather we invest on Piccolo instead. I rather give this guy a chance rather than Zebina, provided that Piccolo does indeed stay with the club.
5. I will still give Birindelli the nod if Balzaretti is injured, but bear in mind that he isn't really a 90 minute player anymore. Use Piccolo instead