Harper's return was a late decision as he received the call to be at Clash of Champions on Friday, according to Dave Meltzer of Wrestling Observer Radio, but apparently he had been training for a ring return for at least a few weeks now. As noted, WWE took extra steps to keep Harper's return a secret last night as they kept his name off the format sheet, and he was kept hidden until right before the Rowan vs. Reigns match.
Harper and Rowan are set to team up to face Reigns and Daniel Bryan, likely at the WWE Hell In a Cell pay-per-view, according to Meltzer. It was noted that WWE brought Harper back because Rowan needed a tag team partner for the feud. There's no word yet on if WWE still has plans for the original outcome of this storyline, which was Reigns vs. Bryan.
The WWE Hell In a Cell pay-per-view takes place on October 6 from the Golden1 Center in Sacramento, CA. As noted earlier, WWE currently has plans for two title matches to take place at HIAC, inside the Cell structure - Sasha Banks vs. RAW Women's Champion Becky Lynch, and "The Fiend" Bray Wyatt vs. WWE Universal Champion Seth Rollins.
On a related note, it looks like The Bludgeon Brothers will be wearing metal band t-shirts instead of the gimmick costumes that they wore during their SmackDown Tag Team Titles reign last year. Rowan's collection of band t-shirts has been a trending topic on social media this summer and the WWE website noted that Harper came out with a band shirt on to match his partner. Besides Harper dropping weight, another hot topic on Twitter after last night's return was how Harper came out wearing a t-shirt for Amon Amarth. Rowan wore a t-shirt for Enslaved.
For those who missed it, above is video from Harper's return.