McKernan showed glimpses of his potential but soft tissue injuries and untimely suspensions meant he failed to cement a regular AFL spot.
McKernan played 16 games in 2019, of which nine were victories and was selected in the Bombers' Elimination Final team.
In a Covid-interrupted season, McKernan played nine of a possible 17 games for the Bombers for four wins, four losses and a draw.
McKernan preferenced the Saints due to their closer proximity to his home, compared with Melbourne's training base at Casey Fields.
[9] He is the younger brother of North Melbourne premiership ruckman and Leigh Matthews Trophy winner Corey McKernan.