Chelsea are set to be without captain Reece James for several weeks and the defender may not return to action until the new year.

James missed the start of the season with a hamstring injury, before returning to make three appearances before the November international break. But the 24-year-old is back on the treatment table after picking up a fresh hamstring injury in training.

Speaking ahead of Chelsea’s Europa Conference League match with German club Heidenheim, Maresca said: “I think the best thing we can do for Reece James is not to talk too much about him. The more we talk, the more pressure we put on him”.

He is not expected to play until at least the end of December, reports the Telegraph, after undergoing a scan this week.

James’s natural deputy is Malo Gusto but the Frenchman is also struggling with injury, and Maresca confirmed that both Gusto and Pedro Neto will be rested in midweek, with one eye on a return against Aston Villa this weekend.

Gusto missed Saturday’s 2-1 victory at Leicester because of illness, while Portugal winger Neto was injured during the recent international break.

“Both have trained with us,” Maresca said. “We don’t take any risks for (Thursday’s) game, but I think both should be available for Sunday’s game.”

Maresca says he will continue with his policy of resting his front line stars for European games, taking several academy products such as Kiano Dyer, Samuel Rak-Sakyi and Tyrique George to Germany.

“It’s an important competition, a European competition. Since we started we have tried to share minutes with all the players in the squad,” he said. “In some of the (Conference League) games, we have also used some young players. So we’ll see. In this moment, it’s like this, and hopefully we can continue in this way.”

Chelsea have won all three of their Conference League games after dispatching Gent, Panathinaikos and Noah, scoring 16 goals in the process, but Maresca is wary of complacency.

“I enjoy every game in this competition knowing that every club tries to make it their big game,” Maresca said. “The issue for us can be that if we are not ready mentally and we underestimate a team, they can hurt us. So we need to be ready.”

additional reporting by Reuters