The Barca boss is currently recuperating in New York following treatment for a cancerous parotid gland and Zubizarreta has revealed that Vilanova's convalescence is going well.
"He's fine. He's recovering and he's in high spirits," Zubizarreta told reporters.
"He is grateful for all the support people are giving him. He has put weight back on and is watching football every day."
It is not yet confirmed when the coach will be back full-time at the Camp Nou.