Kai Havertz is pushing hard for Bayer Leverkusen to agree a deal with Chelsea before the Bundesliga side's Europa League match against Rangers next week.
Havertz wants to move to Chelsea and work under Frank Lampard and only an agreement about the transfer fee is holding up the deal.
Leverkusen value Havertz at £90m but all parties are hopeful a £70m deal, plus add-ons, can be done.
Champions League qualification means Lampard has more money to spend after signing Timo Werner and Hakim Ziyech.
Havertz is back in training with Leverkusen as they prepare for their Europa League game against Rangers a week on Thursday, and the 21-year-old would like the deal completed before that game.
It will be a busy summer at Stamford Bridge with Lampard also looking for a new goalkeeper, left-back and centre-back.
Atletico Madrid have no intention of selling Jan Oblak so any move for him would involve having to pay his £110m release clause.
Ajax goalkeeper Andre Onana wants to move to the Premier League and he would be a cheaper option.
There are question marks over the futures of several Chelsea players, including Jorginho, Emerson, Marcos Alonso, Davide Zappacosta, Michy Batshuayi and Tiemoue Bakayoko.
Meanwhile, Willian could agree a new deal at Chelsea before the end of this week, with the winger's current contract set to expire.