David Moyes is ready to resist Sam Allardyce's efforts to lure Jermain Defoe to Crystal Palace, sources from Sunderland have told ESPN FC.
Defoe, 34, is Allardyce's leading January target following his appointment as Palace manager last week, but the former England forward will not be sold during the transfer window.
Moyes, who succeeded long-standing friend Allardyce as Sunderland manager in July, insisted last week that Defoe was "priceless" and a crucial part of his plans.
But with Sunderland chief executive Martin Bain admitting earlier this month that Moyes would have no funds to strengthen his relegation-threatened squad next month, the former Manchester United manager could be forced to sell in order to raise money to spend during the transfer window.
Senior figures at Sunderland have made it clear, however, that leading scorer Defoe will not leave the Stadium of Light in January.
Defoe has scored 27 goals in 69 Premier League appearances for Sunderland since quitting MLS outfit Toronto to return to England in January 2015.
The former West Ham United, Portsmouth and Tottenham Hotspur striker scored 13 league goals under Allardyce for Sunderland last season as the club secured unexpected survival following months in the bottom three.
That form prompted calls for an England recall for Defoe, and Allardyce considered the veteran for the international squad during his brief reign as England manager earlier this year.
Sources close to Allardyce have confirmed that the Palace manager was hugely impressed by Defoe's professionalism and contribution during his time in charge at Sunderland, but despite the pair's mutual admiration of each other, the Wearside club are prepared to reject any offers for the player.