Ghanaian winger Callum Hudson-Odoi suffered a hamstring injury during Chelsea's Boxing Day win over Watford.
Hudson-odoi came on in the 43rd minute during the first-half after Pedro picked up a knock, only to be taken off in the 85th minute.
Chelsea manager Maurizio Sarri has now revealed that he has been dealing with hamstring trouble throughout the week and he needed to be taken off as a precaution.
"Callum Hudson-Odoi had a hamstring issue last week which flared up in the last 10 minutes and he felt a little pain, which is why he came off," the Italian is quoted by the club's official twitter handle.
Meanwhile, the teenage sensation believes he will return stronger.
"Great performance from the boys, gutted to come off with a hamstring problem but I’ll come back stronger!," Odoi tweeted.
Eden Hazard scored twice as Chelsea won 2-1 at Vicarage Road, with Ricardo Pererya scoring for the hosts.
Hudson-Odoi has been given chances to impress by Sarri this season, with the youngster scoring his first senior goal in the Europa League earlier this month.
Great performance from the boys, gutted to come off with a hamstring problem but I’ll come back stronger!!?????????? pic.twitter.com/0PFQo9MUYo
— Callum Hudson-Odoi (@Calteck10) December 26, 2018