The club's signing last week of Manchester City keeper Costel Pantilimon on a four-year deal sparked speculation in the Italian press that Mannone had responded angrily by putting in a transfer request.
Mannone, however, has responded quickly, firmly denying the claim.
In a press statement, Mannone said: "I don't know where this false speculation is coming from but I want to let supporters know that there is absolutely nothing in it.
"I have not asked for a transfer and I have no intention of doing so."
Mannone joined Sunderland last summer after a stuttering seven years on Arsenal's books and an injury to Republic of Ireland keeper Keiren Westwood in November saw him become first choice keeper.
One highlight of his season was the Capital One Cup semi-final penalty shoot-out at Old Trafford, in which Mannone saved the crunch penalty which knocked Manchester United out and took the Black Cats into the final.
That final preceded a remarkable revival under manager Gus Poyet and Mannone played a significant role as Sunderland avoided relegation having been odds-on to be relegated.
With Westwood and fellow keeper Oscar Ustari being released by the club when their contracts expire this month, it appeared competition had diminished for Mannone.
The arrival of Romania international Pantilimon, however, reawakenes the competition for the keeper's shirt.
Mannone added that he and Poyet had discussed some time ago the club's need to strengthen the goalkeeping department.