"Randy sustained head trauma following his match with Big Show, in which Daniel Bryan interfered, and he was evaluated in the training room immediately afterward," WWE physician Dr. Michael Sampson told WWE.com. "Due to his symptoms as well as his neurological evaluation, he was diagnosed with a concussion. We will be doing more testing to see how he's going to do as far as short term vs. long term."

Orton will not be cleared to compete in the World Heavyweight Championship Elimination Chamber Match this Sunday.

Orton's replacement has already been named as Santino Marella won a Battle Royal to  earn the right to replace Orton in the Elimination Chamber match.

http://www.wwe.com/shows/raw/2012-02-13/orton-suffers-concussion