Hakim Ziyech dislocated his shoulder during the UEFA Super Cup over Villarreal, and he is now expected to remain on the sidelines for a period of time.
In a press conference, Tuchel confirmed that the Moroccan does not require surgery but will be treated conservatively to make his comeback.
Alongside Ziyech, it appears that N’Golo Kante could miss the season opener after picking up an injury. He was substituted shortly after the hour mark on Wednesday.
Tuchel said: “Hakim is out for sure. It will be treated conservatively – we don’t need surgery which is good news.
“There is an issue with N’Golo Kante from the [Super Cup] final we need to sort.”
Aside from the duo, club-record signing Romelu Lukaku will be unavailable for the curtain-raiser as he is still under quarantine after arriving in London.
“We’ve had some exchanges on the phone, exchanges of messages, but right now he is following the protocol and quarantining some more days,” Tuchel added:
The Blues scraped into the top four during the back end of last season after Leicester City failed on the final matchday of the previous league campaign.
The west London giants have since won the Champions League and Super Cup titles and should go into the new season with plenty of expectations.
They are considered by many as the front-runners to compete with Manchester City for the title. The Blues have beaten the Cityzens on three occasions under Tuchel.
Their finishing was a prime concern last season, but the arrival of Lukaku should provide a huge boost in the final third as they look to win their first title since 2017.
Stats from Transfermarkt.com