Diafra Sakho has reportedly had a falling out with West Ham boss David Moyes over bonus payments relating to the striker starting games.
Sakho came off the substitutes' bench for the Hammers' Carabao Cup defeat to Arsenal on Tuesday to try and turn the tide, but the Daily Mail have alleged that he may not have played at all due to a row with Moyes over a lack of starts under the Scot.
According to the report, Sakho's current contract has a clause written into it that states the 27-year-old will be paid a £50k bonus for every match that he starts for West Ham.
That bonus is halved if he instead comes onto the pitch, via the bench, and given that the Senegal international is yet to feature from the off under Moyes, led to a confrontation between the pair ahead of the Emirates clash.
Sakho had to be persuaded to stay by club officials after he threatened to leave north London and head for home, and it remains to be seen what repercussions come of this.
Moyes is known as a strict disciplinarian and will not have taken kindly to Sakho's outburst, but sought to downplay any suggestions of a squabble as he claimed he had "only positive" things to say about the goalscorer.
Sakho has failed to start a Premier League game all season for the Irons, with all 14 of his stints coming from the subs' bench.
Sakho's £50k bonus doesn't cover starts in the cups - ironically the only matches he's been named in the starting lineup for - and was shunned for the matches against Arsenal and Manchester City earlier in December in favour of winger Michail Antonio, who led the line in his stead.
The ex-FC Metz star is believed to be a January transfer target for Cardiff City in the winter window, but the Championship side are not willing to pay West Ham's reported £15m valuation for the injury-maligned attacker.