Heerenveen midfielder Viktor Elm admits his side need to work on their attitude if they want to climb the Eredivisie table.
The Dutch club are currently ninth in the standings but have claimed just one win from their last four league games.
And Elm, who joined Heerenveen from Swedish club Kalmar in 2009, admits the mentality of the team is letting them down.
The 25-year-old told NuSport: "We have good footballers at Heerenveen but it seems that we do not have the heart to win a match. It's just a question of attitude.
"The players of our team are all beautiful to watch. Technically it's perfect. We can play well and we have quite a few times.
He added: "There is currently a lot going on at the club. There are rumours and the atmosphere is sometimes not good."
Saturday's Eredivisie clash between Heerenveen and AZ Alkmaar will be a family affair as Elm and his brother, Rasmus Elm, come face to face.
The match is a crucial one for both teams, who are only three points apart in the race for European football.
The two midfielders, whose older brother David is also a professional footballer with Elfsborg in Sweden, have faced each other numerous times before.
Rasmus, 22, is adamant there will be no nasty challenges flying around on Saturday, although he admits it has happened in the past.
"The first time we had to play against each other was quite crazy," he said. "You could say we went into it not as brothers, only victory counted.
"Everyone was talking about. I did not like it. I would never forgive myself if Viktor got injured."