Chelsea have made an opening £26.8 offer to Zenit St Petersburg for midfielder Leandro Paredes.
Paredes has become the most likely arrival to move to west London following the departure of Cesc Fabregas to Monaco on Friday.
Coach Maurizio Sarri made it clear to the Chelsea hierarchy that he wanted a replacement for Fabregas and the club have also looked at Cagliari star Nicolo Barella.
But the latter has reservations about moving to the capital this month and is also subject of strong interest from Napoli and Inter Milan over a summer move to stay in Serie A.
Paredes, who has earned nine caps for Argentina, had intimated that he wanted to leave Zenit in order to go back to boyhood club Boca Juniors.
However, Chelsea look set to change his mind as they are ready to give him a four-and-a-half year contract with a basic salary worth around £80,000-a-week.
Zenit could still take some convincing to sell at that price as they paid Roma £24m, which included various add-ons, for Paredes in 2017
But Chelsea are under pressure to strengthen in this position and will pay more if necessary. Jorginho has very little back-up and Sarri admitted he would have substituted the Italian during the 2-1 win over Newcastle on Saturday had Fabregas been on the bench because he was struggling so much.