Dawson Mercer
Dawson Mercer's cap hit of $4 million is not the biggest problem in the world, but it isn't ideal either. He is close to a lock for 20 goals a season and has been since his rookie year, but he hasn't improved as much as people were hoping for when he first broke out in the NHL.
Mercer could be traded to a team that takes a chance on his upside. In return, the Devils can get some cap space, a roster spot, and someone who can help them going forward in return.
Mercer isn't good enough to be a full-time top-six guy, but he's not a typical bottom-six forward either. With New Jersey's championship window (Hughes and Hischier's prime) supposed to be open, Mercer may not be great for them in the long term.
Dougie Hamilton
There have been rumors about Dougie Hamilton being traded this offseason. If the Devils are going to do something like that, they better be careful.
Yes, it will free up the next three years from having a $9 million cap hit. However, a puck-moving defenseman of his caliber leaving could be hard to overcome.
They better be sure that Luke Hughes, Seamus Casey, and Simon Nemec are ready for the spotlight if Hamilton is going to be shown the door.
If they were getting back a prominent top-six sniper who is more than a rental, it's a risk worth considering, but they better make sure that replacing Hamilton the right way is something they can do.