According to German media outlet Bild, Bayer Leverkusen have given Chelsea a deadline to complete a deal for Kai Havertz.
The Bundesliga side want transfer negotiations to be completed by August 28, which is less than 10 days away, to avoid distractions in pre-season.
Bild also claim Chelsea have been in negotiations with Bayer Leverkusen to sign Havertz since last week, and are closing in on a deal.
Havertz is expected to become the most expensive German player of all time when he completes his transfer to Chelsea. Timo Werner is currently the most expensive German player after his £53 million transfer to Chelsea from RB Leipzig.
Chelsea boss Frank Lampard is keen on signing the 21 year old Bayer Leverkusen midfielder after he impressed last season with 18 goals and 9 assists for Bayer Leverkusen.