Thibaut Courtois is at risk of missing Belgium's Euro 2016 qualifier with Andorra on Friday, after Chelsea decided to conduct further tests on the goalkeeper's head injury that caused him to be replaced by Petr Cech against Arsenal on Sunday.
The 22-year-old was replaced in the 2-0 win over the Gunners after a heavy blow to the head when colliding with Alexis Sanchez and suffering a cut to the right ear.
Consequently he was replaced shortly after the incident and taken to a nearby hospital, amid fears that he could have sustained internal damage to his brain - a risk the Blues will know all too well after Cech took a blow to the head in a Premier League match with Reading in 2006.
However, the league leaders are keen to keep him in the country so they can further analyse him which would rule him out of the Belgian's clash.
Won't be risked
Boss Marc Wilmots has given the 'keeper a deadline of today to join the rest of the squad, or miss the game in Brussels.
The former Belgium attacking midfielder will accept Courtois' omission against minnows Andorra, but is keen to have him back in time for the sterner test they face on Monday in Bosnia.
"If Courtois comes, we certainly won't take any risks with him," he told The Sun. "We're still waiting for the definitive diagnosis of Chelsea.
"He's almost back but they want to wait before they release him."
Brain charity's concern
After the incident, Courtois played on for a further 14 minutes, leading to brain injury charity Headway voicing their concerns.
Chief executive Peter McCabe said: "It is hard to understand how a concussion was not suspected following the sickening clash.
"The fact the bleeding only became apparent 15 minutes after the injury demonstrates the evolving nature of concussion and highlights why a safety-first approach must be taken."
Chelsea team-mate Eden Hazard is also a doubt for Friday's game with a toe injury.