Manchester United's hopes of qualifying for next season's Champions League were dealt a blow with the news defender Lisandro Martinez is facing at least eight weeks out with knee ligament damage.
The Argentine World Cup winner had only recently returned from a foot injury that has kept him out for most of the season.
However, Martinez's presence had been felt in United's upturn in form in recent weeks.
"Lisandro Martinez has sustained an injury to the medial collateral ligament in his knee and is expected to be out of action for at least eight weeks," United said in a statement.
"We all wish Licha a speedy recovery and look forward to seeing him back on the pitch later in the season."
Martinez is now set to miss most of the remainder of the campaign, although he could potentially return for the final seven Premier League games of the season and the latter stages of the FA Cup.
"He is very sad, very disappointed," said United boss Erik Ten Hag after the West Ham game.
"We feel really with him. First of all, it's a personal disaster when it's really bad, but let's wait for what it is. But also for the team it's really bad because he definitely brings us a lot."
United are sixth in the Premier League, six points adrift of Tottenham and eight behind fourth-placed Aston Villa, who they face on Sunday.
A place in the top four will guarantee Champions League football next season, while fifth could be enough depending on how English sides fare in European competitions this season.