Kristensen has played in only one Premier League game for Leeds this year and has lost his place in the team as the starting right-back to Luke Ayling.
The Danish star played in every one of Denmark’s matches last year, playing the full 90 minutes in two World Cup games.
However, Bruun believes there is now cause for concern for Denmark coach Kasper Hjulmand as Kristensen has lost his place for Leeds.
The ex-Denmark star believes that Kristensen was seen as a player with huge potential, but now doubts have arisen over his selection as Hjulmand is not likely to pick players who are second fiddle in their team.
Speaking to Danish broadcaster TV 2, Bruun said: “There was a great belief in Rasmus Nissen Kristensen.
“But doubts have arisen now, because Hjulmand does not want to select players who are decidedly reserves with their club team.”
Ayling has re-emerged to become the first-choice right-back at Leeds and it remains to be seen when the Danish international gets regular game-time at Elland Road again.
Before the year turned, Kristensen played 14 games for Leeds in the Premier League this season and he also played in every one of the Whites’ FA Cup games.
