Eden Hazard will not feature for Chelsea against Derby County in the Carabao Cup but is "much better" and should return to full training on Wednesday, according to assistant manager Gianfranco Zola.
The Belgium international, who leads the Premier League scoring charts with seven goals in nine games this season, was not involved in Chelsea's 4-0 win over Burnley on Sunday due to a back injury sustained against Manchester United.
Head coach Maurizio Sarri said after that match that Hazard's fitness remains of critical importance, and Zola said that he is on track to return to the team when Crystal Palace visit Stamford Bridge on Sunday.
"He's certainly much better," Zola said. "Not sure today, maybe tomorrow he's going to join us in training. I don't think he's going to be involved in the game [against Derby] but he's looking quite good for the weekend, so we are pleased because he's such an important player for us."
Sarri's other fitness doubt is Pedro, who was substituted against Burnley after complaining of severe stomach ache.
Olivier Giroud also has fatigue in one of his legs, but youngster Ethan Ampadu could be back in contention after returning to full training following a knee injury this week.
Ross Barkley registered two assists and a goal against Burnley in his most impressive performance of the season so far, and Zola said there are elements of Barkley's game that remind him of Derby boss and Chelsea legend Frank Lampard.
"I thought Frank Lampard making the box was exceptional," he said. "The best midfielder I've ever seen having that quality, attacking the box, getting in the box in the right moment. That's why he scored so many goals. Ross likes to play more with the ball, to be involved more in of the action.
"What I've seen in the last two or three weeks is his scoring ability is coming on very well. I know from the beginning he had this ability. At first it wasn't showing, because he was very much involved learning tactically what the team needs him to do, but now he's getting that freedom is taking out all of his ability.
"I think there are some differences between him and Frank, although there are similarities. Both of them have unbelievable potential."
Zola also had kind words for Chelsea loanee Mason Mount, who will play against his parent club for Derby at Stamford Bridge on Wednesday.
"I came across him [Mount] when I first came here," Zola said. "I was analysing the players we had on loan. He was one of the first players I analysed and I said 'this player is for us.'
"This was the plan, to keep him at least for preseason with us. But then an opportunity to send him to play in England in such a competitive league like the Championship came and the club decided it was good for him.
"I like him very much, because he's one of those players that has the mental speed to work out things very quickly. You can see that in the way he plays.
"Physically he has to improve. The Premier League is a different level. But he's getting on very well. I'm pleased for him and I'm looking forward to seeing him playing at Stamford Bridge. I'm sure he'll be up for it and it will be important to get even more indications for us."