#2 As a part of the Wyatt Family
Strowman was recently paired with Dolph Ziggler and Drew Mcintyre, collectively known as the 'Dogs of War'. However, the breakup of the stable has already been teased several times as WWE prepares plans for McIntyre's singles run. That means Braun would be left alone when the breakup happens and could do with a new team to have his back.
With the Shield working together again and fighting beside Strowman's current rival Roman Reigns, it makes sense for Braun to reunite with the Wyatts in order to even the odds. The Wyatt Family making a shocking appearance to confront the Shield would bring back old memories and would, thus, generate a huge pop from the crowd.
With Rowan out injured, Harper and Bray both off the TV, it would be a wise move to reintroduce them together as the Wyatt Family, who would help Strowman fend off the 'Hounds of Justice'.