......He's 19 years old.Imo that weight for his height makes him small, Height doesn't always = size. Marner is about 6'0 he is small (175) Amirov weight wise is about the same size as 5'9 Brendan Gallagher.
Edit: I'd also rather have someone shorter and stickier than tall and lanky given the choice aswell based on centre of Gravity and implied muscle mass.
6'1" 185lb at age 19 is far from small. Your logic is daft.
Nylander at the same age was close to 165lbs and by his early-mid 20's he hit 200lbs at a similar height. Amirov likely rounds out between 190-200lbs at peak physical maturity.