The Argentine superstar extended his deal with the Liga champions in February, committing himself to Barca until 2018.
Messi has struggled with numerous injuries this term, but has still managed to fire 14 goals in as many games for his club.
Reports in Spain earlier in the season had claimed that Messi had demanded improved terms, just months after penning a new deal, but Faus - who heads up Barca's economic operations - insists no offer will be forthcoming, despite rumours of interest from free-spending Premier League side Manchester City.
He told Radio Catalunya: "I don't see any reason to improve the contract of someone who had their deal enhanced just six months ago.
"In any event, that's an issue for the sporting staff.
"However, while Sandro Rosell is president the possibility of selling him (Messi) is zero."
Barca coach Gerardo Martino remained tight-lipped about the matter when speaking ahead of their UEFA Champions League clash with Celtic on Wednesday.
He said: "I did not participate nor do I want to participate in the contractual issues with players.
"Leo has his value but, like with all players, his worth is made of lots of different things."
