As noted, Bray Wyatt suffered a calf injury very early in his match with Roman Reigns on 4/14 in Milan at a WWE live event. The word going around within WWE is that he’d be out four to six weeks.
Wyatt is teasing his return to the ring via Twitter:
https://twitter.com/WWEBrayWyatt/status/725077124504276992
The original plans for Payback were for the Wyatts to wrestle the League Of Nations in a multi-man tag team match, but it appears that the match is off as Erick Rowan, and Braun Strowman has not appeared on WWE TV since Wyatt suffered his injury.