Sunderland are awaiting developments on striker Daryl Murphy's proposed move to Celtic.
The clubs have agreed terms and the 27-year-old was given permission to talk to the Glasgow giants on Thursday night.
Black Cats assistant boss Eric Black said on Friday: "The clubs have agreed terms, it is now down to the player.
"He has been given permission to go and speak to them, which I think he was doing last night."
Republic of Ireland international Murphy, who joined the Wearsiders in a £100,000 move from Irish club Waterford in June 2005, has struggled to command a regular place at the Stadium of Light in recent seasons, particularly under new boss Steve Bruce.
He spent the second half of last season on loan at Ipswich, where he scored six goals in 18 appearances.