Originally published on ProWrestlingSheet.

Pro Wrestling Sheet has learned Randy Orton sustained a concussion last month at SummerSlam, and it's why he didn't wrestle Bray Wyatt tonight at Backlash.

Our sources say the concussion occurred during Orton's bloody encounter with Brock Lesnar ... and although there's no word on when it happened in the match, we're guessing it was sustained during one of the many canned-ham-sized elbows he took to the skull.

Initial tests indicated he’d be good to go — which is why he was promoted for Backlash up until the event started — however, due to the type of injury, WWE officials instead made the decision to go with Kane vs. Wyatt in a No Holds Barred match at the last minute.

For those who missed it, Orton was written out of the match after Bray attacked him backstage earlier in the night. He eventually re-appeared later and caused Wyatt to lose to his surprise opponent.