Celtic insist they are not in negotiations with Roy Keane over a possible move for the former Manchester United midfielder.
The 34-year-old left Old Trafford last week when his contract was brought to a premature end.
Celtic Park is known to be a favoured destination for the former Republic of Ireland captain and the Hoops quickly opened the door for possible discussions on Friday.
But, amid claims that the Bank of Scotland Premier League leaders have made contact with Keane, the club maintain any formal negotiations have not started.
A Celtic spokesman said: "Celtic have not, at this point, entered into contract negotiations with Roy Keane or his representatives."
Portsmouth and West Ham are the latest clubs to have voiced an interest in Keane.
Manchester City, West Brom Bolton and Wigan are also monitoring the situation as the midfielder assesses his options.
Hammers boss Alan Pardew said: "I wouldn't dismiss it. I haven't explored what Roy wants to do because that is probably what is going to happen - it will be what Roy wants to do.
"But certainly I haven't closed the door on bringing a player of his stature to this club because that is the sort of player we want to look at.
"We have a great base here of young players, a good squad and a good spirit and to jump to the next level we need to bring in real quality players."
Earlier, Portsmouth chief executive Peter Storrie also admitted the Fratton Park club were looking at the possibility of signing the controversial midfielder.
He said: "If we could bring Roy Keane to Pompey, it would be fantastic, but in what role I don't know.
"However, we are in a queue of about 40 clubs who have registered an interest with his lawyer.
"We would like to talk to him if he wants to talk to us. I am unsure whether Roy Keane wants to stay as a player or get into coaching."
