Right-back Carl Jenkinson has suffered an injury which could cause him to miss the rest of the season.
West Ham's official website stated Jenkinson's knee injury is 'significant', and he will be sent for further tests.
Jack Sullivan, son of co-owner David Sullivan, said via Twitter that Jenkinson is not expected to play again in 2015/16.
Carl Jenkinson’s injury is far more serious than we thought and he is out for the rest of the season.— Jack Sullivan (@jsullivanwhu) January 26, 2016
The defender is in the second year of his loan spell at West Ham, and had been expected to return to Arsenal at the end of the campaign.
The injury puts an end to his hopes of being selected in England's Euro 2016 squad. Jenkinson has been capped once by the Three Lions.
West Ham are well equipped to cope in his absence, having just signed right-back Sam Byram from Leeds United.
Jenkinson was expected to challenge Hector Bellerin at Arsenal next season, with Mathieu Debuchy unlikely to stay at the club. If his injury is as serious as described, he may not even be back in time to state his case in pre-season.
Here is a look at how West Ham fans reacted to the news via Twitter...
shame for carl jenkinson. he has been good at west ham and looks as if he will be out for a while. step up sam byram. good luck lad. #coyi— Purge V | Angus (@IGreatPurge) January 26, 2016
Jenkinson has been great for us... Especially last season! This season has just not worked out for him! Thank you for everything Carl #COYI— Diafra Payet (@Diafra_Payet) January 26, 2016
And here is what Arsenal fans have had to say...
Arsenal players even get injured out on loan. Jenkinson #afc— GöönerGössip (@GoonerGossip) January 26, 2016
Our injury curse is exceptionally consistent. It's ALWAYS one for one. Now, Welbeck walks out, Jenkinson walks in. Like, obligatory. #Afc— Robert Mutebi (@mrobans) January 26, 2016