It is a mix of size and skill that allows you to be ready. AHL is more physical than NHL so many kids no matter how skilled can't play there. And if they have over that skill, they might skip to the NHL.
Yager is a guy that is too skilled to learn much at the junior level, but not physically ready to go pro. His best development was somewhere else. Poulin and Howe were two examples of guys that were too physically mature to get much out of their last junior year, but don't have the skill to play in the NHL at that age. They'd have been better in the AHL or at least college hockey or playing overseas.
Koivunen is currently tied for third in the AHL is points. Yet at would have been the end of his junior career he looked like he may never succeed at that level.
Even McGroarty, a guy thought to be close to NHL ready and a big player, at the start of the season, struggled big in his first month against grown men. That just took a month though. 12 goals and 34 points in 42 games since is fine for a 20 year old and one of the youngest guys in the league.
My TLDR, the problem isn't that guys can't go from juniors to the AHL. Most aren't ready for it even of they dominate juniors. It's that they don't go from juniors to a league that would help them develop and waste their age 19 season.
If the awful transfer agreement wasn’t in place then a lot more junior players would go to the ahl and it would alter the league’s makeup making the league better physically for said players.
