I listen to a Podcast and they suggested that Strowman is still without a partner right before the match is about to happen and Angle forces him to choose somebody. In haste Braun grabs Curt Hawkins and that's how his underexposed losing streak ends. I kind of like the idea of a team where one member is petrified of the other, and it protects Braun because he'd basically be in handicap matches for the duration.
Alternatively I'd like to see Joe be his partner. It would be such a badass team until the inevitable split and it's not like Strowman is going to be challenging for the Universal Championship until at least SummerSlam.