Manchester United revealed on Monday that Lisandro Martinez had injured his medial collateral ligament during the Premier League clash with West Ham United on Sunday afternoon.
The Argentina international was forced off the field in the 71st minute of the match, having initially tried to continue after damaging his knee in a challenge with West Ham's Vladimir Coufal.
Man United said in their statement that Martinez would be out "for at least eight weeks", which is a huge blow for the Red Devils and the centre-back, but there had been fears that he had damaged his ACL.
Here, Sports Mole takes a look at the matches that the 26-year-old could miss, with the 20-time English champions still active in two competitions - the Premier League and FA Cup.
Should Martinez need two months to recover, he would miss eight Premier League matches for the Red Devils and at least one clash in the FA Cup.
Man United have three straight league games against Aston Villa, Luton Town and Fulham before facing either Bristol City or Nottingham Forest in the fifth round of the FA Cup on February 28.
The Red Devils will be back in Premier League action at the start of March, facing a trip to the Etihad Stadium to take on Manchester City, which will prove to be the fifth match that he misses.
Man United will be back in league action against Everton on March 9, before a home game against Sheffield United ahead of the international break.
Man United will finish March with a trip to Brentford, before taking on Chelsea at Stamford Bridge on April 3.
Much will depend on Martinez's recovery, but under the current timeframe, he could potentially be available for the Premier League clash with Liverpool at Old Trafford on April 6.
As it stands, the Argentine will miss nine matches, but he would also be absent if Man United make it through to the quarter-finals of the FA Cup, which will take place the weekend of March 16.
If that occurs, the league game with Sheffield United will need to be rearranged, and it is unclear what date that fixture would be moved to, but there are plenty of options due to the club's absence from Europe.
Martinez has already missed 22 matches for Man United this season following a foot operation, which he underwent in September after initial surgery in April failed to fully fix his fractured metatarsal.
It has therefore been a hugely frustrating season for the Argentine, who has been restricted to just 10 appearances in all competitions, with eight of those coming in the Premier League.
Martinez made his return against Tottenham Hotspur on January 14 before starting against Newport County, Wolverhampton Wanderers and West Ham.
The Argentine starred for Man United last season, and his absence is a huge blow for the Red Devils considering his leadership skills and ability to play out from the back.
Harry Maguire and Victor Lindelof have both recently returned from fitness problems of their own, though, and the pair's importance has risen during a key period, with Man United looking to advance in the FA Cup and challenge for a Champions League finish in the Premier League table.
