The Denmark international had just returned to match fitness after being out for five months through injury for the first leg, but when the final whistle went he was complaining about the same hamstring giving him jip.
So the 20 year old missed the weekend game against NEC in the Dutch League and after having scans it was revealed that he will be out of action for three more weeks.
Ajax, who are already 2-0 down from the first leg, are already without first-team regulars Gregory van der Wiel, Eyong Enoh, Derk Boerrigter and Kolbeinn Sigthorsson, this latest st-back does not improve their chances.