Cesc Fabregas will not feature for Chelsea against former club Arsenal as he deals with a "very unusual" injury, but Mateo Kovacic could make his debut, head coach Maurizio Sarri said on Friday.
Both players missed Chelsea's 3-0 win over Huddersfield Town on Saturday, with Kovacic having only arrived at Cobham on a season-long loan deal from Real Madrid three days earlier and Fabregas remaining at the training ground to continue his rehabilitation.
The Spain international remains unavailable but Kovacic is likely to be on the bench, though Sarri said he is some way short of peak fitness.
"Fabregas is out for this match. I hope he will be able to be on the pitch [training] next week. I'm not sure," Sarri said. "[It's] nothing serious, but he has a very unusual injury. [It's] nothing serious, but he has a pain, not in the knee... near the knee. But not in the knee."
On the subject of Kovacic, he added: "I think Mateo will be very useful for us. He's a very technical player. In this moment, he has to work. I think he's not ready now for 90 minutes, but maybe, tomorrow, for the first 30 or the last 30 minutes he could be used.
"I expect a lot from him because, for me, he's a very great player. In my opinion, he can improve more. I think he can play in any of the three positions in midfield. He's a very good offensive player, but he has improved in the defensive phase in the last two years in Madrid."
Sarri is expected to stick to the starting XI that beat Huddersfield, with Eden Hazard once again among the substitutes as his fitness is carefully managed after missing most of preseason.
There are no such concerns about N'Golo Kante, however, who played the full 90 minutes at the John Smith's Stadium.
"Kante, for physical characteristics, is very quick to be ready to play," Sarri said. "He played very well in the last match. He is ready. But, for the other players from the World Cup, I think it's a little bit different."
Alvaro Morata is also expected to be given another chance to rediscover his scoring touch at the head of Sarri's 4-3-3, despite having found the net just once in his last 10 Chelsea appearances in all competitions.
"I am not worried about Morata," he said. "Morata is a very great player. I think that, in this moment, he needs only to gain confidence. He needs to score as all the strikers in the world do, I think. He needs to gain confidence, but he's improving so I'm not really worried about him."
Sarri is expecting Arsenal to provide a stiff test on his first competitive match at Stamford Bridge, despite the limp nature of their 2-0 home defeat to champions Manchester City on the Premier League's opening weekend.
"For everybody, it's difficult against Manchester City, I think," he said. "I think that [Unai] Emery is a very good coach. He won three times the Europa League. He won in France with PSG.
"And I think Arsenal, this season, will be competitive. They will be able to fight for a place in the Champions League."