Ajax have confirmed Abdelhak Nouri remains in an induced coma after collapsing during a friendly match against Werder Bremen.
Saturday's match at Lindenstadion in Hippach was abandoned after Nouri lay down on the ground, with paramedics tending to the 20-year-old after ambulances entered the playing surface.
Nouri was flown to hospital via helicopter and Ajax provided an update on his condition on Monday.
"Appie's heart is functioning normal and appears to be undamaged," Ajax said. "It is however too soon to say anything about his recovery, as his brain function cannot be tested properly as long as he is kept asleep."
Ajax coach Marcel Keizer said earlier on Monday that pre-season testing on Nouri had shown the player was "100 per cent fit".
"We are waiting on the results of the neurological tests," Keizer told AT5. "The results could come on Tuesday. He is in good hands and is being well cared for.
"Now we hope, it's an important result for us. Everyone is feeling tense. Our doctor stayed there to keep in contact with the hospital.
"His family is there, they get all the updates first and then we hear it. I tried to distract myself on Sunday but just got on my bike. I tried to occupy my mind, but it didn't work."
Keizer confirmed Nouri's Ajax team-mates have been told it is their decision whether or not they report for training as they await updates on his recovery.
"It did not matter if the players came to training or not, everyone loves Appie. We encourage everyone to talk about it, cry together," Keizer added. "He has a very good relationship with his room-mate Hakim Ziyech. But there are guys who have played football with him for 12 years. It's not easy.
"I just hope he gets better. He represents Ajax for me, dominant and attractive football. That's Appie. We are not so concerned with the qualifying round of the Champions League, it's all about Appie first."