Leicester are awaiting international clearance to complete the transfer of Adrien Silva from Sporting Lisbon.
The Premier League club are confident they managed to sign the Portugal midfielder in time, after being granted a two-hour extension to get the deal done after Thursday night's 11pm deadline passed.
Silva's move hinged on Danny Drinkwater sealing a switch to Chelsea and the window closed with Silva at Leicester's training ground and Drinkwater at Chelsea's Cobham base.
The paperwork for both deals was submitted on time and Drinkwater was announced as a Chelsea player at 1.30am on Friday morning but because Silva is an international transfer, Leicester have been waiting on clearance to announce the deal.
However, Sporting have said in a statement: "Sporting Club de Portugal... informs the market that we have reached an agreement with Leicester City Football Club for the definitive transfer of the sporting and economic rights of the professional soccer player Adrien Silva.
"The registration of the same (player) is awaiting confirmation of FIFA."