hes the third best mid
He's not even the sixth best.
A half-fit Prestia at the start of the season was providing more in the midfield than Vlastuin.
Lambert has established himself in there, Caddy will get more time in there with Townsend in the side (and once we get another key forward next season) and Miles is a better midfielder than Vlastuin, ditto for Grigg, who spends time there.
Vlastuin is best suited at HB and it would be a gross error putting him back there. His form in the last few weeks has more than proven that his position should not have been tampered with. He could barely get his hands on the ball as a midfielder.