After Justin Robinson received his full scholarship to play for Duke, Brennan Besser is one of two (the other being freshman Mike Buckmire) walk on players for the team. Because he's a walk on player, he won't see playing time at all unless Duke is blowing out the opponent. Nevertheless, Besser's role on the team is to help the team in practices and in hyping the other guys up while on the bench, as shown in the video below.
Taken during the 2016-2017 season, watch Amile Jefferson talk with Brennan Besser and Antonio Vrankovic about the energy they feed off to the other players and how they contribute to the overall energy during games.