Not many members of the 2019 Giants outperformed expectations.

One of the few re-signed Friday, just three days before NFL free agency opens.

Inside linebacker David Mayo is back, The Post confirmed, after he made 82 tackles in 16 games (13 starts) and became one of the team’s highest-rated defensive players by Pro Football Focus. He totaled 61 tackles in 59 games (four starts) during four previous seasons with the Panthers.

Mayo signed with the 49ers last offseason but was released just before the regular season began and earned his stripes with the Giants on special teams.

The Giants still are expected to prioritize inside linebacker in free agency and the NFL Draft, after cutting starter Alec Ogletree to save $8.25 million against the salary cap. Mayo signed a three-year deal, according to The Athletic.