As for when to begin letting Parsons train at maximum exertion for combine events, the closest thing Capretta has to a model comes from previous prospects whose college teams failed to make a bowl game. Those players typically begin training in early December, a few weeks before many bowl-bound prospects start to prep. The recent trend of top prospects opting out of bowl games has added to his early December group -- Capretta noted Denver Broncos 2019 first-round pick Noah Fant and L.A. Rams 2020 second-rounder Cam Akers, as examples. Even that, however, isn't an ideal comparison because those players typically arrive with nagging injuries suffered during the season, requiring time to heal before more intense training can commence. Parsons and 2020 opt-outs, by contrast, won't have played a down this fall.
Source : https://www.nfl.com/news/micah-parsons-guarding-against-overtraining-for-nfl-after-opt-out