Rangers boss Warburton wants to sign a back-up striker this month.
Sam Allardyce has confirmed that Dame N'Doye is on his way to Sunderland.
The Frenchman is still looking for his first win as Villa boss after 10 games at the helm.
There is widespread interest in the West Bromwich Albion star.
Wolverhampton Wanderers were beaten 1-0 by West Ham United at the weekend.
Sunderland, Crystal Palace and West Ham are all interested in Khouma Babacar.
Aston Villa continue to be linked with potential new arrivals.
Mark Warburton is said to be keen on signing Brentford midfielder Toumani Diagouraga for Rangers.
Pickford made his debut in the weekend's FA Cup defeat to Arsenal.
Liverpool may have just stopped Leeds United signing one of their January transfer targets.