Aleksandar Mitrovic and Aboubakar Kamara had a row in Fulham's training ground gym last week, Sky Sports News understands.
The incident happened just weeks after Kamara grabbed the ball from designated penalty taker, Mitrovic, before missing a spot-kick in Fulham's match against Huddersfield.
Mitrovic went on to score the winner in that game, but Claudio Ranieri was enraged at Kamara, saying the forward had disrespected all those at the club.
Kamara scored in Fulham's following match, a 4-1 loss to Arsenal, but was not included in Ranieri's 18-man squad for their trip to Burnley last weekend - after his latest disagreement with Mitrovic.
Fulham lost 2-1 to Burnley, leaving them 19th in the Premier League and five points off safety.
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Following the defeat the club's vice-chairman, Tony Khan, told a fan to "go to hell" in a tweet after the fan demanded that the American "leave my club please".
Fulham play Tottenham on Sunday, live on Sky Sports Premier League.