Tomas Soucek has suffered a groin/adductor problem and was not taken off as a precuation during West Ham's loss against Liverpool on Monday night.
The Czech midfielder, on-loan from Slavia Prague for the remainder of the campaign, was sensational in the first half as the Hammers went into the break level at 1-1 with the Premier League champions elect.
Late on in the half though, Soucek injured his adductor/groin according to manager Moyes and was struggling at half time to even make it out for the second half.
He lasted just three minutes after Jon Moss blew his whistle to restart the game before he was down on the turf and asking to be taken off, replaced by Pablo Fornals.
Soucek had been showing plenty of promise in his three outings for the Hammers since joining on loan and was outstanding in the first half at Anfield, winning five aerial duels in midfield, sticking his foot in and making darting late runs into the box as the Reds couldn't contain him.
Moyes was asked by football.london for an update on the midfielder post-match and he said: "He picked up the injury just before half time and it meant that he was struggling. We knew at half time and I thought he had been fabulous as well.
"It is a big loss to us, especially in the second half as we didn't have an awful lot where we could tighten things up, really.
"I am hoping he will be OK but it looks like a groin or adductor injury from over stretching in the first half.
"I'd loved to have said it was a precaution but it's genuine He even did well to get out for the second half."
The Hammers suffered a galling defeat in Liverpool having come from 1-0 down to lead -1 thanks to goals from Issa Diop and Pablo Fornals. Mo Salah equalised after a owler from Lukasz Fabianksi and Sadio Mane sealed all three points late on as Liverpool continued their romp towards the Premier League title.
