When looking over the Patriots' roster, 71 players are under contract.
Teams are allowed up to 80.
With this in mind, it wouldn't be surprising to see the Patriots sign a few more players in the coming days. Such players are most likely to be rookie free agent types, while the team could also revisit the possibility of a few veterans they previously had in for workouts (e.g. receiver Mike Furrey).
Running back, receiver and linebacker are a few areas on the roster that could use a numbers boost.
From a team perspective, using the full 80-man limit is a way of maximizing opportunities. Until draft picks sign, they don't count against the limit. So the Patriots can actually have up to 92 players until the draft picks sign, which offers a chance to get others into the system and see if they show potential to help in the future.
It figures to be a crowded locker room in New England.