West Ham are believed to be considering lodging an official complaint over Fulham's team selection last weekend.
Fulham boss Roy Hodgson left out six regular first-team players for the game at West Ham's fellow Barclays Premier League relegation strugglers Hull on Saturday.
Hull won 2-0, a result which leaves the Hammers outside the drop zone only on goal difference.
The Premier League have not yet received a complaint but West Ham are understood to be unhappy with Fulham, who were resting players ahead of their Europa League quarter-final tie against Wolfsburg.
The league has recent experience of such cases, having found Wolves guilty of fielding a weakened team earlier this season.
The Molineux club were handed a £25,000 suspended fine after making 10 changes for a game at Manchester United in December.
Wolves manager Mick McCarthy today leapt to Hodgson's defence, even though a Hull revival could see his side dragged back into the relegation scrap.
McCarthy said: "I haven't got a problem with it. I am not bothered what team they played.
"It is just something that the high and mighty, who tend to look at their own teams, don't like when it is happening.
"It is about making the most of your squad and utilising your squad to the best of their abilities. That is what I did and that is what Roy did.
"Fulham are still in Europe, so good luck to them. They are probably safe with the points they have got and don't forget we have still got them to play this season.
"But good luck to Roy and if it means he wins that Europa League then I will be thrilled for him. He has had a great season.
"If they have still got anything to play for when they play us and want to play a weakened team against me, I will be delighted."
Hull manager Iain Dowie pointed out his team were hardly given a walkover by Fulham at the KC Stadium.
Dowie, a former Hammers striker, said: "That's for West Ham to worry about.
"Fulham's statistics showed their best work ethic of the year, so that really puts to bed any misnomer that it wasn't a fair contest.
"You can only beat what's on the field. The precedent has already been well set in the Carling Cup and no-one seems to complain.
"Roy Hodgson's done a magnificent job, he's arguably the manager of the year and his team worked harder than in any other game this season.
"It's something I'm not going to be distracted by. We beat a very, very good Fulham side."
Wigan also remain in danger of relegation, lying just four points above Hull.
Latics boss Roberto Martinez had no problem with Hodgson's selection, although his side do play Fulham in the middle of their two-legged tie against Wolfsburg, at Craven Cottage on Sunday.
The Spaniard said: "As a manager you always make decisions that can help your team.
"Roy Hodgson and Fulham have had such a successful season, they know exactly what they have got behind the scenes and know what they need.
"For anyone to criticise another football club when they are in such outstanding form is very foolish.
"Roy Hodgson has got to make the decisions to help his team achieve their aims for the season."
Former Sheffield United manager Neil Warnock may watch developments with interest.
Warnock, who is now in charge at QPR, was furious when Manchester United fielded an understrength side against West Ham in the final game of the 2006-07 season.
The Hammers' victory that day allowed them to survive while the Blades were relegated.Reuse content