Former Republic of Ireland international midfielder Keane was in charge at the North East club with Sbragia as his assistant until late last year, before agreeing with Sunderland Chairman Niall Quinn to leave his post.
Since Keane has been appointed manager at Portman Road, the Cork born Irishman has made several comments in reference to his former club and the level of confidence at the club, something which has annoyed Sbragia.
He said: "It just seems that, if he wants a bit of publicity, he says something - but why not talk about Ipswich? Why's he always talking about Sunderland?
"Roy left this club. He's not here and we don't talk about him, but for some reason he keeps coming back.
"I don't know why. Maybe he still thinks he's the manager. Maybe he's just bored and has nothing to do, so he thinks, 'I'll have a go at Sunderland'.
"I think he should just really concentrate on Ipswich. He's back in football. He should enjoy it.
"He knows the reason he left Sunderland and I know exactly why he left. I wouldn't want to go into print and say exactly what I know about what he said and what he did.
"But I don't know why he keeps talking about Sunderland. He's left Sunderland. I could go into more detail, but I won't."
Click here for a basic profile on Town boss Roy Keane.