The Premier League outfit made the announcement on their official Twitter account, stating that 25-year-old has been taken to hospital.
The Hammers did not state for how long Tomkins will be sidelined, but he looks certain to miss Saturday’s Premier League clash against Arsenal at the Emirates Stadium.
Tomkins, who can play both as a centre-back and as a defensive midfielder, joins a number of his West Ham teammates on the sidelines.
West Ham manager Sam Allardyce will be without central defender Winston Reid, and strikers Carlton Cole and Andy Carroll, while Enner Valencia is doubtful.
Carl Jenkinson is unavailable for Saturday’s match as he is on loan from Arsenal, which means that midfielder Cheikhou Kouyate could feature in central defence.
West Ham are currently 10th in the Premier League table with 39 points from 28 matches, 12 points behind fifth-placed Liverpool.
Following the news of Tomkins’s injury, West Ham fans took to social networking site Twitter to have their say on the situation.
Below are the best reactions:
@whufc_official I can make myself available to play tomorrow if needed!! Players seem to be dropping like flies!!!!— Jamie Penfold (@jamie_penfold) March 13, 2015
Wow Tomkins out for the season, can't beat a good old fashioned injury crisis, standard West Ham form!!#COYI— Ian Tilbury (@Tillroll78) March 12, 2015
Loan out Doneil Henry. Reid and Tomkins get injured. Always the way.— West_Ham_COYI (@West_Ham_COYI) March 12, 2015