In all honesty, it's the Devils only chance or looking at a trade option.
Team has a boatload of young forwards but no promising defenders outside of Severson, Santini, and Rykov who is a few years away from coming over. If Devils want to compete under Schneider, Hall, Henrique, Palmieri, and Zajac/Greene's final good years, they need to make a big splash in free agency.
The only good thing right now is with the cap space and cap flexibility, they could afford to overpay for a guy like Shattenkirk or even a guy like Alzner and plan around it down the road. Schneider, Hall, Henrique, and Palmieri are all signed to very fair deals.