From his interview with Weiss at the beginning of the season:
While Belichick admitted that the cap caught up to the Patriots this season, he sees this as a one-year period to reset their salary cap for the future.
“Again, because of our cap situation — in this particular year, this is kind of the year that we’ve taken to, I would say, adjust our cap from the spending that we’ve had in accumulation of previous years,” Belichick said. “We just haven’t been able to have the kind of depth on our roster that we’ve had in some other years."