Julen Lopetegui was involved in a furious fight with Jean-Clair Todibo during West Ham's defeat to Arsenal, talkSPORT understands.
The incident occurred during the Hammers' damaging 5-2 home defeat to the Gunners last Saturday, which saw the east London side concede all five of their goals in the first half.
Tensions flared between Lopetegui and Todibo, who joined on loan from Nice with an option to buy for £35m in the summer, during the defeat.
The 24-year-old defender expressed his frustrations to his coach at half-time.
This caused a heated dispute between the couple.
Despite the crash, Todibo played the rest of the game, without other veteran center backs on the bench.
He missed West Ham's 3-1 defeat at Leicester on Tuesday night due to a persistent groin problem.
Lopetegui has already been involved in a disagreement with another West Ham player since becoming manager in the summer.
He fell out with Mohammed Kudus in the 1-1 draw at Brentford in September after dragging him on at half-time.
Almost £130m was spent on new players over the summer after Lopetegui arrived as David Moyes' successor.
However, the former Wolves manager's job at the London Stadium hangs in the balance.
West Ham are 14th in the Premier League standings, six points above the relegation zone with a goal difference of -9.
And talkSPORT understands that West Ham are Lopetegui is being fired due to his disappointing start to the campaign.
The Hammers board are expected to hold crucial talks on Wednesday to discuss their future following their defeat at the King Power Stadium.
Sporting director Tim Steidten, who originally advised owner David Sullivan not to appoint Lopetegui, is understood to be pushing for a change.
talkSPORT previously reported that Steidten has already held talks with the former Borussia Dortmund boss and Edin Terzic, who was part of West Ham's coaching staff.
Former Denmark coach Kasper Hjulmand has emerged as a surprise candidate for the job.
Meanwhile, former Porto boss Sergio Conceicao and former Chelsea and Brighton boss Graham Potter are other possible replacements.
Lopetegui was named Moyes' successor in May on a two-year contract, with the option of a third.
Speaking after Leicester's defeat on Tuesday, the Spaniard said: “It's a frustrating night because we deserved a lot more. “Playing football is not easy.
“We had 31 shots into the opponent's area, normally you have to win this game. We had many opportunities but we didn't score.
“Tomorrow we will begin to look for the next challenge, knowing that we can change the situation.
“They want to win for themselves, for me and for the club.
“Football is about winning. Today is a day when we deserved much more.
“The next one will be the most important, we must be focused.”