Sunderland have reached an agreement with Lyon for Belgian winger Malick Fofana, but the transfer remains unresolved after Crystal Palace made a late attempt to hijack the deal.

Fofana had agreed to join Sunderland in a package worth up to £30 million, including a fixed fee of approximately £25.7 million and a further £4.3 million in performance-related bonuses. He was given permission to travel for a medical and was expected to sign a five-year contract containing an option for an additional 12 months.

However, Fofana had not completed his medical with Sunderland when Palace entered the race. The London club subsequently reached its own agreement with Lyon and began trying to persuade the 21-year-old winger to move to Selhurst Park instead.

The dramatic late development has left Fofana deciding between Sunderland and Crystal Palace. Sunderland remain hopeful of completing the deal and have reportedly made arrangements for the player to undergo his medical in France if necessary.

Arsenal had also shown interest in Fofana but chose not to pursue the transfer at Lyon’s valuation. The Gunners had explored attacking additions following Leandro Trossard’s departure, but Sunderland moved ahead after Arsenal stepped back.

Fofana is coming off an injury-disrupted season in which he made only 16 appearances after undergoing ankle surgery. He has started the new campaign more positively, scoring twice in his first six matches for Lyon.

The Belgian winger’s preference is understood to be influenced by Sunderland’s European qualification and the opportunity to work under manager Régis Le Bris. Nevertheless, Palace’s improved proposal has created genuine uncertainty, meaning the transfer cannot be described as completed until Fofana passes his medical and signs the contract.

The situation has become one of the most dramatic stories of deadline day, with both clubs holding agreements with Lyon and Fofana yet to make his final decision.