The Bluebirds are desperate to get the club-record deal done in time for their match against Newcastle on Saturday as the Ligue 1 club want him to play one final game on Sunday
Cardiff have reportedly agreed a deal for Nantes forward Emiliano Sala for a club-record £18million.
Sala, 28, has agreed personal terms and is waiting for permission from the French club to fly out to Cardiff for a medical.
However, Sky Sports News claims that the deal will not be completed in time for him to play in their huge Premier League clash at Newcastle on Saturday as Nantes want him to play one final game for them against Angers on Sunday.
The Argentine, who has 12 goals in 19 Ligue 1 appearances this season, flew to the UK on Monday for talks with Bluebirds boss Neil Warnock and chief executive Ken Choo.
Cardiff have also agreed terms with Everton to sign Oumar Niasse on loan until the end of the season.