Ben Chilwell is a major doubt for Chelsea's Boxing Day clash against Arsenal.
The England international - one of seven major first-team signings made by the Blues in the summer transfer window - limped out of the 3-0 win over West Ham United with a twisted ankle.
As a result, he could sit out the big game against the Gunners.
Emerson Palmieri, who replaced the defender against the Hammers, is on standby if Chilwell is ruled out, while Marcos Alonso will be hopeful of a surprise recall.
Chilwell had a scan on Tuesday to determine the extent of his injury and Chelsea head coach Frank Lampard delivered an update on the left-back - and Reece James - ahead of the trip to the Emirates Stadium.
"They're both doubtful so I can't give you an answer at the moment, we're not sure whether they will be fit for either game," Lampard said in his pre-match press conference.
With that said, Chilwell has been rather optimistic regarding the injury.
Taking to social media following the Blues' win over West Ham, the 24-year-old was hopeful the ankle problem wasn't so bad.
"Back to winning ways," he wrote on Instagram. "Hopefully injury is not so bad."
The aforementioned post prompted a reaction from one of Chilwell's teammates.
Tammy Abraham, scorer of two goals against the Hammers, reacted to being tagged in the post by replying with a four-word message of encouragement.
"My brother," he said. "Speedy recovery!"
Whilst Abraham and Lampard face an anxious wait regarding Chilwell's availability, it has already been confirmed that Hakim Ziyech will miss the game against the Gunners.
"No, he won't be fit for Arsenal," Lampard revealed "It's a muscle injury so we need to wait for it to recover.
"Not a long-term concern and we hope to have him back in a week or so.
"That's football when players are playing every two or three days."
