Experience counts, he's 21 in 6 months, if your playing against teenagers at that age you do have an advantage that they don't have and development years that they haven't hit yet
When he's playing pro against pro sized men were going to get a much better read on him and his game, at that size defending a Matthews size forward takes some not insignificant abilities
Those guys are forwards, besides Spurgen and Krug it's not that easy listing off guys 5'10 and under playing consistent bottom pair minutes let alone top 4
He can certainly make it but his defensive game in the pro ranks will decide what he is, he won't get consistent minutes until he can prove that at least so I'm withholding judgement until then