The Manchester Evening News reports that with Januzaj's long term future at United still uncertain, van Gaal could still sanction his departure if it means being able to bring in either Seamus Coleman or Marquinhos, from Everton and Paris Saint-Germain respectively.
Both clubs expressed interest in taking Januzaj during the transfer window before being knocked back. However, things could change if United's notoriously cutthroat boss is not sufficiently impressed with the player by the time the summer window opens.
The chance to negotiate a better deal for either Coleman or Marquinhos could also make losing the 19-year-old yet more appealing.
Januzaj represented one of the most promising talents to emerge from the club's famed youth academy when he made his debut under David Moyes last season, but has since struggled to make his mark this season.
He recently also admitted that he is struggling to play in van Gaal's philosophy, especially in a 3-5-2 formation, in a surprisingly frank interview with United's official matchday programme.
"My favourite position is as a no.10 or a winger. The system really can make it more difficult for me to play there, but I have to keep working. There are lots of players here and I can play in different roles - it's just a case of taking my opportunities," he said.