The 28-year-old centre-back was stretchered off in the first half of Sunday’s (01.11.26) third-round tie at London Stadium, which the Irons eventually won 2-1 after extra time to book a place in the fourth round.
Speaking after the match, Nuno said: “Yeah, it was a neck injury. It was a nasty one. He’s in pain. Let’s assess him.
“But it was a neck injury. Let’s see. For the couple of days he’s going to need to rest.”
Mavropanos was injured in the 39th minute following a QPR corner and remained on the pitch for several minutes as medical staff attended to him.
The Greece international was eventually taken off on a stretcher to warm applause from all sides of the ground, with the severity of the incident leading to 10 minutes of added time at the end of the first half.
West Ham took advantage of that extended period when winger Crysencio Summerville, 24, fired the hosts into a 1-0 lead just before the break.
However, Championship side QPR responded after the interval, with Richard Kone, 22, equalizing in the 65th minute to take the tie into extra time.
Despite the disruption caused by Mavropanos’ injury and a below-par second half, West Ham found a way through thanks to new signing Taty Castellanos, 27, who scored his first goal for the club to secure a morale-boosting victory.
The Argentina international striker rose highest to power home Summerville’s left-wing cross with a bullet header, sealing the win and sparking jubilant celebrations inside the stadium.
Speaking to West Ham TV, Castellanos said: “I’m very happy. We knew it was a very important match for us, for the team’s confidence.
“I think we’ve done a really good job. I’m very happy about my first goal in this shirt; I felt really good and very pleased.”
Castellanos acknowledged the wider significance of the win for a West Ham side looking to build momentum in the second half of the season.
He said: “It really is very important given the situation we’re going through. This is about working day after day, training session after training session.
“In the end, we all have to do things right together and keep working on this growth, which will be good for everyone.”
