Honestly, I can't see Porter's decision significantly affecting Hewitt's status one way or the other -- except for the following fact:
Hewitt must know by now that he's gonna have to pull a rabbit out of his hat to win enough games next season to keep his job for year 5 and beyond. I highly doubt that a rail-thin 6-10 kid is going to play significant minutes for a coach in that situation; if he does, that likely means our roster has been ravaged by injury, suspension or some other foolishness.
So that may make it easier for Hewitt to sell Porter on the redshirt. If Porter realizes that he's not going to play much other than garbage minutes, hopefully he and his people will be smart enough to save that year of eligibility for the back end of his career.