Chelsea also confirmed that striker Olivier Giroud has signed a contract extension which will keep him at Stamford Bridge next season.
Giroud moved across from Arsenal in January 2018 and his existing deal had been due to expire at the conclusion of the current campaign.
Giroud told Chelsea's official website: "I am delighted to continue my journey and adventure at Chelsea. I
can't wait to get back to playing and enjoying competitive football with my team-mates.
"I'm looking forward to wearing the Chelsea shirt again, especially in front of our fans at a full Stamford Bridge, whenever it is safe to do so."
In other news concerning Frank Lampard's squad, Willy Caballero has agreed a new one-year deal.
The club has exercised their option to trigger a 12-month extension in the goalkeeper's contract. Caballero told the club's official site: "I am very happy to make this announcement. It is a privilege to be part of this Chelsea squad and the Chelsea family, at one of the most historic clubs in the Premier League.
"It is a difficult time for everyone right now so I feel blessed by this opportunity and truly appreciate it."