The expectation was that the Patriots would take it slow with Jones, and that he would contribute primarily as a pass-rusher in his first year in the league. Those expectations should probably change, though.
It's not just that he's getting the reps; it's that he's maximizing those reps, and looking good. His competition hasn't been light, either; he has lined up against left tackle Nate Solder and has won his fair share of those matchups.
As Bedard points out, the Patriots may be trying to cram it in for Jones to make sure he's ready, or they could be trying to get him up to speed so that they can decide with conviction as to whether they should start him. It would be a surprise, though, to see Jones get all these first-team reps and then not be the full-fledged starter Week 1.
Whereas Jones' role was in doubt, very few ever questioned that Hightower would factor into the defense early and often. The question was, how would he factor into the defense, and how would his role impact Spikes' role.