Claims of tension between the Hearts squad and manager Daniel Stendel are "a lot of rubbish", says Steven Naismith.
It has been reported concerns about the German coach's communication skills and tactics had reached the boardroom.
It comes with Hearts bottom of the Scottish Premiership, a point adrift of Hamilton Academical with 11 games left.
"I was surprised. In the winter break it was crystal clear for everybody to understand and the manager's English is pretty good," said forward Naismith.
Speaking to the club website, he added: "The bottom line is that it's been individual errors - one player making a mistake or being out of position - that's cost us."
Hearts came from two goals down to draw with 10-man Hamilton at Tynecastle on Saturday and have won just once in their last 15 Premiership games.
They travel to Paisley to face 10th-placed St Mirren on Friday, with Naismith describing it as a "must-not-lose" game.
"We'll need a much better performance than the weekend and need to be defensively solid and confident enough on the ball to create chances," he said.
"The result at the weekend is one of those shock results you want to use to spark a reaction. But the second half shows we're still fighting as a group to push forward and get out of this mess.
"That is the only way to get out of this. If anybody - coach, player, staff - goes their own way, they will be excluded from the group. It's as simple as that."