Advocaat has helped Sunderland improve since taking the reins, but persistently overlooking Duncan Watmore seems bizarre.
Watmore has been one of Sunderland's development side's star players throughout the campaign so far, but both Poyet and Advocaat have appeared reluctant to pick him.
Prior to departing, Poyet suggested in the Mirror that Watmore was close to making his Premier League debut and Advocaat reportedly called him up to the senior squad for his first training session after taking charge, according to the Shields Gazette, but the 21-year-old is still waiting for his first chance.
It is hard to know what else he can possibly do to break into the team, either. Every match Sunderland's Under-21 side play, Watmore seems to star.
If he is not scoring, he is creating and he appears to have all the attributes that are desperately lacking for the Black Cats' first-team at the moment.
His inexperience seems to be holding him back, though, and Advocaat does not appear to be brave enough to put him in his starting line-up.
That is somewhat surprising as, although Sunderland are in the thick of a relegation battle, they appear to have little to lose by giving Watmore his opportunity.
The more experienced attackers in the Black Cats' squad are hardly firing on all cylinders at the moment and Watmore could be the secret weapon they need to fire them to safety. They just need to play him.