More info:
As noted, WWE’s original plan for Sting at SummerSlam was for him to team up with Roman Reigns and Dean Ambrose in a six-man tag team match against the Wyatt Family (Bray Wyatt, Luke Harper and Erick Rowan).
However, with Rowan being out with an injury, WWE is looking for someone to replace Rowan in the match. It’s always possible that Sting will not wrestle at all, but just make an appearance.
Update: Dave Meltzer said on Monday’s episode of the Wrestling Observer Radio show that Sting is set to be brought into the storyline late in the game, likely as a big surprise.
Update 2x: WWE is discussing three ideas that they can do with Sting. First, there could be a new member of the Wyatt Family introduced in the next week or two, which results in Reigns & Ambrose getting Sting as their mystery partner, or there will be an Ambrose injury and Sting will take his spot, or they’ll drop Sting completely from SummerSlam.
Sting is said to be in great shape right now.