We finally have confirmation of this move:
#Jets signed exclusive-rights free agent Isaiah Mack— Aaron Wilson (@AaronWilson_NFL) April 17, 2023
Mack, who was claimed off waivers at the end of the season, will be under contract at the minimum for 2023 but nothing is guaranteed so he will have to compete for a roster spot.
Universally-respected Jets insider @sixtyeightgames was the first to report the Mack re-signing a few weeks ago:
BREAKING: Jets to ERFA tender Isaiah Mack (probably)— tsjc68 (@sixtyeightgames) March 13, 2023