Slovenia claim that the Wembley pitch has been "completely ruined" by the NFL game last week, ahead of their clash with England in their Euro 2016 qualifier on Saturday.
England boss Roy Hodgson had already claimed last week that he was unhappy about the surface being used for Sunday's clash between the Dallas Cowboys and Jacksonville Jaguars. However, after training on the pitch on Friday night, Slovenia are not pleased either.
One Slovenia official said in the Daily Mirror: "Down the wings, it is fine, but there is a 10m square patch right in the middle where the pitch is completely ruined. There is no grass there at all."
Slovenia boss Srecko Katanec added that the pitch could be a disadvantage to England.
"If there is rain or mud, it is, up to a point, an advantage for team that is defending because ball is harder to control," he said.
"The guys play weekly matches at big stadiums, huge crowds, maybe they'll be impressed but that should not have an effect on the performance. Because of all that Wembley means, playing here should be a huge motivator for all the guys.
"Three points are available but we have six already so they should not feel too much pressure at Wembley.
"Congratulations to Rooney for his 100th cap, you have to play a lot of years to get that achievement, but as far as our perspective, we will try to make it a bad experience for him."