#2 Daniel Bryan

Daniel Bryan’s documented history of head injuries was just one part of his forced two-year retirement from competing in the WWE.
Amongst the series of injuries that would plague Bryan, would be a head injury he suffered in 2011, when he took on the then WWE Champion Alberto Del Rio.
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Meeting on the August 19th edition of SmackDown Live, the smug Del Rio, who had won the gold earlier that week at SummerSlam, tagged Bryan with a cheeky kick to the face.
Whilst it may not have seemed much, the blow knocked out The Eco-Friendly Superstar, as Del Rio had to forcibly move Bryan out of a pinfall attempt so the match wouldn’t end.
Coming to the end of the match, Bryan would find himself in Del Rio’s armbar, and whilst Bryan may have come up short against The Aristocrat, he did get a receipt, nailing Del Rio with a series of especially stiff kicks of his own, with Del Rio has admitted he deserved.