In the meantime, here's every signing the Black Cats have made in January over the last decade, and a look at where they are now.
5. Ignacio Scocco - January 2014
The one-time Argentina international never lived up to the hype that greeted his arrival at Sunderland, and he lasted just half a season. Currently, he's turning out for River Plate, and has re-found his scoring form. (Photo by Alexis Lloret/Getty Images) Photo: Alexis Lloret
6. Liam Bridcutt - January 2014
After one and a half seasons at the club, Bridcutt was loaned out to Leeds United, who he subsequently joined on a permanent deal. Now, he's with Bolton Wanderers on loan from Nottingham Forest. (Photo credit should read PAUL ELLIS/AFP via Getty Images) Photo: PAUL ELLIS
7. Jermain Defoe - January 2015
What a signing this was! The lethal finisher scored 37 goals in his two and a half season spell with the Black Cats, before moving to Bournemouth in 2017. He's now tearing it up on loan with Rangers. (Photo by Ian MacNicol/Getty Images) Photo: Ian MacNicol
8. Jan Kirchhoff - January 2016
The towering defender played a vital role in Sunderland staying up in the 2015/16 season. He left when his contract expired in 2017, and is now at third tier German side KFC Uerdingen. (Photo by Michael Titgemeyer/Getty Images for DFB) Photo: Michael Titgemeyer