He hasn't even turned 21. Larsson is 20 years old and 330 days old, or thereabouts. The Devils have 7 defensemen on their roster, let's go down the list and see which ones of them were in the NHL at that age... Anton Volchenkov had played 38 games in the NHL at that age, that's a good start. The rest of the Devils' D combined played.. hmm, looks like a big 0.
Larsson is turning more physical every game, as he gets more confident that part of his game will progress.