The Panthers only have 19 players under contract in 2016, the fewest in the NFL. You can probably jettison Johnson and Johnathan Stewart off that team as well as kicker Graham Gano. They will pick some players back up- Luke Kuechly will have his option exercised, Newton, Davis, and Olsen should all be extended- but still we are talking about a very limited roster beyond this season compared to a majority of the NFL.
They should have huge amounts of cap space in 2016 as a quick run through of some projected cuts and placeholder cap charges should leave them with over $60 million in cap room if no big free agents are brought in and the cap continues to rise at a $10M a year pace. That is the season where they should be considering spending, not so much this one.