The 26-year-old could be sidelined for several weeks, potentially missing as many as 10 matches, according to multiple sources who spoke to BBC Sport. The injury occurred towards the end of the first half of Wednesday's encounter when Lacroix sprinted in an attempt to block a Liverpool shot.
The defender was forced off the pitch, leaving Chelsea concerned about his availability for the coming months. Although the club has yet to confirm the full extent of the injury, manager Xabi Alonso indicated that the player would be unavailable for the immediate fixtures.
Speaking ahead of Saturday's Premier League meeting with Manchester United, Alonso confirmed that Lacroix would miss several weeks and was unlikely to return before the upcoming international break.
The setback represents a significant blow for Chelsea, considering how important the defender has become since arriving from Crystal Palace during the summer transfer window in a £52 million deal.
Lacroix has started 10 of Chelsea's 11 matches across all competitions this season, establishing himself as one of Alonso's most trusted defensive options. Only attacker Morgan Rogers has featured more frequently for the Blues during the campaign.
Chelsea have several alternatives in central defence, including Levi Colwill, Wesley Fofana and Josh Acheampong. However, the club's defensive options have also been affected by injuries, with Jorrel Hato and Aaron Anselmino currently unavailable.
Alonso expressed confidence in the players who could step in during Lacroix's absence, highlighting Fofana's performance against Liverpool despite his missed penalty during the shootout.
The Chelsea manager praised the defender's consistency, physical strength and overall contribution, insisting that he would remain an important player for the team.
Alonso also confirmed positive updates on other members of his squad. Goalkeeper Emiliano Martinez is being fitted with a specially designed protective mask as he continues recovering from a broken jaw. Meanwhile, midfielder Moises Caicedo escaped injury despite concerns following Wednesday's match against Liverpool.
Chelsea currently sit fifth in the Premier League standings with 13 points from eight matches. However, their defensive record remains a concern, having managed just one clean sheet during that period.
Lacroix's potential extended absence could therefore create further challenges for Alonso as Chelsea look to maintain their position in the league and compete across multiple competitions.
