The Barcelona director reports that the Argentine superstar is in high spirits as he continues his recovery from a hamstring problem that is set to keep him out until January
The 26-year-old picked up a hamstring injury in Barca's 4-1 Primera Division win over Betis on November 10 and has since been out of action.
Messi is expected to be sidelined until early January and Zubizarreta has made it clear that his recovery is going according to plan, while remaining confident that the Blaugrana can cope without their star player in the interim.
"Messi's recovery is going reasonably well and he's in good spirits," the Barcelona director told the club's official website.
"He is the best player in the world but, when we don't have him, the others have to be able to compete because they're also among the best.
"Over a season, you need all of them and they always have to respond by playing the top-class football required at Barcelona."