Chelsea fear defender Maxence Lacroix is set for a lengthy lay-off after suffering a serious hamstring injury.

Multiple sources have told BBC Sport that the France international, 26, could be out until January, meaning he could miss up to 10 matches.

The setback occurred at the end of the first half of Wednesday's Carabao Cup loss to Liverpool on penalties, as Lacroix sprinted and attempted to block a shot.

Sources inside Chelsea, including manager Xabi Alonso, have been guarded on the length of the absence.

When asked about Lacroix's injury at his media conference before Saturday's Premier League visit of Manchester United, Alonso said: "Max, he picked up an injury, and we expect that he's not going to be ready before the international break. So he will be a few weeks out."

The injury is a blow for Alonso, who has started his £52m summer signing from Crystal Palace in all but one of Chelsea's 11 matches across all competitions this season.

Only attacker Morgan Rogers has played more than Lacroix for Chelsea this season.

The Blues have a six-man centre-back group featuring Levi Colwill, Wesley Fofana, Josh Acheampong, Jorrel Hato and Aaron Anselmino as alternatives, although the latter two are also currently injured, with others having also lined up at full-back.

Asked about the potential replacements, Alonso added: "With Max's injury, we have Wes, we have Levi [Colwill], Josh [Acheampong], he could play as well as centre-back.

"Jorrel when he is back with the team [is an option]. Wes has played [and] even if he missed the penalty [in the shootout], I think that he had a good game.

"He was consistent, he was strong and I saw many positives from his performance. We know the level that he has had and he's going to be important."

Alonso also revealed that goalkeeper Emiliano Martinez is having a special mask fitted to play while recovering from a broken jaw and midfielder Moises Caicedo avoided injury despite concerns after the midweek clash with Liverpool.

Chelsea are fifth in the Premier League with 13 points from eight matches, but have kept only one clean sheet in that period.