Karlsson burst onto the scene internationally last season; wearing the captaincy for Sweden at the Under 17 Championships and following that up with a very impressive performance as an underager with the Swedish entry at the Under 18 Championships. The 6-foot-1 forward has already filled out to 203 pounds and has a motor that is rivaled by few prospects at this age. Karlsson is a tireless worker who is always making an impact with his hardwork and physicality. The 17-year-old is relentless on the forecheck and is excellent at creating turnovers and driving offensive zone puck possession with great board-work and puck protection. Karlsson is underrated offensively and his ability to be around the puck bodes well for him at the next level as he should develop into a forward who is capable of complimenting a first or second line centre.