Chelsea snapped up Denis Zakaria on loan from Juventus on transfer deadline day, and Chelsea have the option of a purchase clause in the deal.
The 25-year-old midfielder will wear the number 20 jersey at Chelsea.
The other transfer deadline day signing Pierre-Emerick Aubameyang will wear the number 9 jersey – a jersey number believed to have a curse at Stamford Bridge.
Meanwhile, Chelsea boss Thomas Tuchel has said he’s happy with his summer signings.
“We will use the stability to grow, to build a group and influence each other in a positive way,” said the Blues boss.
“I saw a reaction yesterday, and today we had a good training session. The cards are on the table. We will use it as a kickstart, it’s needed. We have the chance to start the season new tomorrow, a home game, with the players that are available. I have the feeling everybody is ready to show up.
“If we don’t get tough, we will get punished. We will show a reaction. It’s proven we can do it with this group.
“We need to find the right spirit and attitude in all the matches. We are now using the momentum we know who is in the squad, and we will show a new face.”