The ninth annual WWE Night of Champions is set to take place on Sept. 20, 2015, at the Toyota Center in Houston, Tex. The show will feature every WWE title in the promotion being defended, and, so far, only four matches have been announced. In other news and rumors, Seth Rollins is tentatively planned to retain his WWE Title while losing his US Championship.

Seth Rollins (c) vs. Sting for the WWE World Heavyweight Championship

"The Vigilante" Sting showed up on WWE Raw during the unveiling of Seth Rollins' bronze statue to set his sights on the WWE Title. The Authority officially announced the match on the WWE Network. This will be Sting's second WWE match.

In a report from Sportskeeda, the current plan for the main event is for Rollins to lose his US title against John Cena and retain the WWE title against "The Vigilante." According to F4W Online via Wrestle Zone, Sting was originally planned to be the mystery partner of Dean Ambrose and Roman Reigns against The Wyatt Family in their six-man tag team match.

WWE has a habit of changing plans up until the event, so everything is not set in stone.

Seth Rollins (c) vs. John Cena for the US Championship

John Cena asked for his rematch for the US Title against Seth Rollins and Stephanie McMahon obliged. Rollins bragging that his better than Triple H is the WWE's way of "planting the seeds" of a possible face turn of Rollins, as reported by Bleacher Report.

According to Wrestle Zone, WWE confirmed that Cena was okay after an injury scare last week, but his overall health will factor in the booking decision of who wins this match.

Nikki Bella (c) vs. Charlotte for the WWE Divas Championship

Charlotte won the Beat-the-Clock Challenge on WWE Raw to get the chance to beat Nikki Bella for the Divas Title. In a report by eWrestlingNews, the current plan is for Charlotte to win the Divas Title before Nikki Bella breaks AJ Lee's record for longest title reign with the rematch taking place at the Night of Champions.   

Roman Reigns, Dean Ambrose and a Mystery Partner vs. The Wyatt Family

The feud between all these men will continue in a six-man tag team match. It will mark the debut of the new Wyatt Family while a mystery partner will help Reigns and Ambrose. According to Wrestling Inc, Baron Corbin will make his main roster debut based on an image from WWE.com that was quickly taken down.

Another possible mystery partner is injured Wyatt Family member Erick Rowan, as reported by Inquistr. Rowan is currently sidelined after tearing his bicep last June with an approximate recovery time of four to six months.