Tim Krul is unlikely to make his Ajax bow any time soon as he continues to work his way back to full fitness following his loan move to the Eredivisie.
The 28-year-old Newcastle United goalkeeper, who joined Peter Bosz's side in August, had only just returned to training following a cruciate ligament injury.
The former Dutch international had been out of action since October 2015.
He was seen as a replacement for Jasper Cillessen following his move to Barcelona, but has since seen deputy Andre Onana take the number one jersey at the club.
Ajax boss Bosz told De Telegraaf: "Tim is a great guy to work with but he's an optimist. When he came to us, we had the idea that he would work with us in full within two weeks.
"I like his enthusiasm but he wanted to participate with the first team before he had joined any group training.
"We have to be realistic and that would have been dangerous. What he wanted to do we just couldn't do."
He added: "[The situation with Onana] was obviously intended to bridge the short period between the departure of Jasper Cillessen and Tim being fit. But Tim was not fit and Andre has done well and is reliable.
"All of that comes into consideration for the choice for the rest of the season. On the one hand it's a luxury for us, but naturally for Tim it's a nasty situation."