Last time a Leaf forward under 20 made the team?

[LeafsNation75]

Kadri played a game for Toronto when he was 19 out of training camp. And then Wilson immediately sent him down because OMG TURNOVERS! that was probably the last time a prospect forward made the Leafs under 20 years old

That was a one time emergency call up and they had no choice to send Kadri back to the OHL after that game.