Hakim Ziyech suffered an injury on his Chelsea debut to leave Frank Lampard sweating on his fitness ahead of the new season.
The summer signing was handed his Blues debut in a pre-season friendly against Brighton at the Amex.
But an ankle knock meant Ziyech needed treatment from the Chelsea medical staff.
He was eventually forced off which will come as a blow to the west Londoners who begin their campaign back at the Amex on September 14.
Before his afternoon was prematurely ended the Moroccan played a crucial role in Timo Werner's opener.
His excellent pass found Callum Hudson-Odoi who nodded the ball into the path of the German who slotted home.
It took Werner less than four minutes to open his account for the Blues following his move from RB Leipzig.
Lampard opted to start Ziyech, Werner and Hudson-Odoi in attack.
It is unclear who the Blues boss sees as his first choice attackers with so much depth at Stamford Bridge.
Kai Havertz could yet be added to their ranks as a mega-money move from Bayer Leverkusen nears.
Christian Pulisic is another option with the American enjoying a fine end to last season following a slow start.
Werner will be up against Olivier Giroud and Tammy Abraham as he looks to lead the Chelsea attack.
Giroud wrestled his way into first team contention midway through last season having been a peripheral figure for a long time.
He had looked set to leave in January but ended up staying in what proved to be a masterful decision.
