Grant was charged with a crusher tackle offence at the back-end of the game on Penrith fullback Dylan Edwards.
The 76th-minute offence was in vain as Melbourne eventually fell by just four points to the Panthers, ending their season and hopes of making a third grand final in four seasons.
The Queensland representative star has been hit with a Grade 1 charge for the tackle, which carries a base penalty of 200 points.
His relatively clean record and no carry over points though means he can escape with a single week on the sidelines if he takes an early guilty plea. If he fights and loses however, it would bump the penalty up to two weeks at the start of 2022.
Grant's impact off the bench yesterday was limited by Penrith's stone wall defence, with Grant forced to play hooker for the best part of an hour following Brandon Smith's injury and failed HIA, which ruled him out of the remainder of the contest.
The news of his impending suspension comes despite Penrith trio James Fisher-Harris, Stephen Crichton and Nathan Cleary all being ruled free to play in the grand final, the former duo only with fines, and Cleary escaping without a charge for a dangerous lifting tackle on Kenneath Bromwich which was put on report.