Manchester United winger Alejandro Garnacho has sent a heartfelt message to Lisandro Martinez after news that the Argentinian defender could be out of action for nine months after he suffered a cruciate knee ligament injury.

The centre-back was in tears as he was stretchered off during Sunday's 2-0 defeat at home to Crystal Palace. Martinez was left stricken on the Old Trafford turf following a tussle, which seemed to spark the innocuous injury.

Ruben Amorim will be without one of his defensive mainstays for the rest of the season as United battle to salvage the campaign with a respectful league finish - as well as run in the Europa League and FA Cup. However, they could be without the former Ajax defender for an extended period of time with the typical recovery time around nine months.

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In a post to his Instagram story, Garnacho sent a message to his international teammate saying: "You will come back stronger, our warrior," with a red heart and strong arm emojis.

"Licha is really important for us, not just as a football player, but as a character, especially in this hard moment, now it’s time to help Licha like he’s doing for so long," United head coach Amorim said on Sunday.

"I think it’s a bad situation, let’s wait to assess things with the doctor but I think it’s a serious situation."

Reports in Argentina confirmed the injury is as serious as first feared on Monday evening but it wasn't enough to spark United into late action during deadline day for the winter transfer window.