Chelsea forward Nicolas Jackson has been ruled out for up to eight weeks with a hamstring injury.
Jackson, who has scored nine goals and provided five assists in 23 Premier League appearances this season, had a scan this week after suffering the injury in the 2-1 Premier League win over West Ham United last Monday and faces a lengthy period on the sidelines.
“Nico will be out until the intentional break, probably available after that,” said Chelsea head coach Enzo Maresca ahead of their Premier League match at Brighton & Hove Albion on Friday.
“We knew that it was a muscular problem, but we did not know how important it was because his reaction was quite good we did not think it was a big injury.
“Unfortunately he had a scan a few days ago and it is an important one, it will be around six to eight weeks.”
Who are Chelsea's options up front?
Christopher Nkunku, who has only made three league starts this season, largely playing in cup competitions, filled in up front for Chelsea in their 2-1 FA Cup defeat at Brighton last weekend. The France international has scored 13 goals in all competitions this season.
Other options include 19-year-old Tyrique George or using Cole Palmer as a “false nine”.
“Christo [Nkunku] is a solution but not the only solution," said Maresca. "I said many times I consider Christo a very important player from the start.
“We are working to find a different solution. It can be Christo but also a different kind of player.
“Pedro [Neto], Noni [Madueke] or even Tyrique [George] - they can try and be a solution for us. Jadon [Sancho] has different kind of skills.
“When you don't have a proper No 9, you need to change the way you play.”
Chelsea's next five PL fixtures
Who else is out for Chelsea?
Marc Guiu has been ruled out with a “long-term injury” also suffered in the win over West Ham.
Another forward, Joao Felix, was loaned out to AC Milan on Deadline Day last week.
Elsewhere, Romeo Lavia and Benoit Badiashile are still returning from their respective injuries while Wesley Fofana remains a few weeks away from full fitness.
“Marc Guiu will also be out for a while. Romeo [Lavia] is in the process to come back with us. Benoit Badiashile exactly the same,” Maresca added.
“Wes Fofana started to work with us two days ago. That means he still needs two or three weeks to be 100 per cent fit. But at least he has started to work with us.”
Before the international break, Chelsea also face Aston Villa, Southampton, Leicester City and Arsenal as they look to cement their position in the top four. The Blues are currently two points clear of Manchester City and Newcastle United in fifth and sixth respectively.