Krul - United's current longest-serving player - spent the first part of the campaign with Ajax as he recovered from a ruptured anterior cruciate ligament.
The eight-cap Netherlands international has made 185 appearances in all competitions during his time on Tyneside and signed a one-year contract extension at St. James' Park in the summer.
He joined Newcastle from ADO Den Haag in the summer of 2005, aged 17.