Sunderland's Championship rivals rocked by transfer embargo ahead of January window

The embargo comes as a consequence of Cardiff City’s failure to pay the first instalment of the £15million transfer fee to French club Nantes for the purchase of Emiliano Sala. The figure stands in excess of £6m with interest.

The Argentine tragically died in a plane crash over the English Channel in January 2019 whilst flying from France to complete his move to the Cardiff City Stadium.

Cardiff are 20th in the Championship and look likely to be in a relegation scrap for the rest of the season after being placed under a transfer embargo with the window set to open on January 1.

Cardiff confirmed before their recent game against Blackpool that there is a three-window embargo in place.

However, Bluebirds boss Mark Hudson insists the embargo is hopeful the club will solve the problem heading into the New Year. He said: "The communication has been clear from the chairman. That is we are under an embargo right now, but the continued proceedings that are going on are to open that up.

"I'm aware of what can and can't be done but it is an ongoing situation, so we have to wait and see how it goes behind the scenes.

"If we do have a window, because there's still lots of ongoing proceedings behind the scenes, we will see what we can do because it is not definitive that we won't [be able to sign anyone]."

"If we are [under an embargo], with the group that we have got, we've got players coming back into it and showing signs of development as well," he said.

"We all plan to see what we can do [in the transfer market] but at the moment we are developing what we have got in the building, because the window is not open yet."

Sunderland faced Cardiff City at the Stadium of Light in the Championship back at the beginning of November. The Bluebirds won the game 1-0. The two clubs next square off in Wales on April 10.