Boqvist had 35 points (13 goals, 22 assists) in 51 games for Brynas last season after a wrist injury sidelined him for all but 23 games in 2017-18.
Tomas Monten, who coached Boqvist for Sweden at the 2018 IIHF World Junior Championship, said he improved his strength and toughness in 2018-19.
"He was able to create more, and not just by way of his speed and skill," Monten said. "Personally, I think he would be better off playing another year in the SHL and for the national team. He's good in the open ice, with good speed, hands and vision. But I still think he needs to learn how to create more inside the dots."
Boqvist, comfortable at either left wing or center, is privy to the fact he must stand taller in the tough areas.
"I know I need to get harder in the corners and I've gotten stronger," he said. "Playing in those areas becomes easier when you have confidence to play that way. I've been working at it, so hopefully I'll be even better when training camp starts."
Devils assistant general manager Tom Fitzgerald isn't placing any expectations on Boqvist.
"He's a talented player who's going to get a chance to make our team, but needs to show us that," Fitzgerald said. "He needs to be a playmaker, get to the inside of the ice at the NHL level. You can't play the perimeter in the NHL because the rinks aren't big enough. If you want to produce, you need to get to the inside. He knows that, so now it's a matter of producing."