FAYETTEVILLE, N.C. -- The ringing in WWE Champion John Cena's ears was louder than ever. He held the back of his throbbing head and grimaced as WWE officials tended to him after Raw. At first, The Champ shrugged away the officials. But then he sighed and reluctantly let them flash a light in his eyes.

Thanks to his SummerSlam opponent Randy Orton, and two straight RKOs at the end of Raw, this was a scene that had become way too familiar to Cena. Just days ago, the Legend Killer had knocked him cold when he attacked him from behind on Saturday Night's Main Event and RKO'd him on a steel chair. The force of the blow mangled the chair and made the capacity crowd in New York City's Madison Square Garden gasp. (WATCH)

A normal athlete may have opted to take time off or would have been sidelined for weeks after being forced to kiss a steel chair. But not John Cena. With his championship defense against Orton at SummerSlam less than a week away, he is determined to turn back the challenge of the Legend Killer once and for all. And he doesn't want to do it just for himself, but also for the legends and Superstars -- people he respects and admires, such as Shawn Michaels, Dusty Rhodes and Rob Van Dam -- that Orton has put on the shelf with cold, calculated precision. (WATCH: Legend Killer's Greatest Hits)

Still, Cena may be showing more heart than smarts. Observers worry Cena will be putting more than his WWE Championship on the line this Sunday. They worry that his very health and career will be in jeopardy when he steps into the ring against Orton. And Orton would not hesitate to take advantage of Cena's injured head and neck at SummerSlam. Read the preview to their match at SummerSlam ...

"Being that those areas are already weak and traumatized, he's [Cena] liable to suffer a significant head injury, maybe even a cracked skull [if Orton kicks him in the head or RKOs him]," said WWE physician Ferdinand Rios. "I don't know why he would want to subject himself to more injury that could be the end of his career. But people feel they can do things even though they know they're hurt. And he's one of them."

Monday night, Cena was still suffering from the effects of the brutal attack, but he tried not to show how hurt he really was. The Champ was seething and his nostrils were flaring when he stomped to the ring and tried to confront Orton. But Cena's eyes told the real story -- they were slightly glazed, and he seemed sapped of energy. And that didn't help him when he battled the monstrous Snitsky in a Mr. McMahon-ordered non-title match.

Anyone would have difficulty with Snitsky, but Cena appeared to be a step slower than usual against the mustard yellow-teeth stained ogre. And Orton must have been grinning ear-to-ear when he saw that Snitsky targeted Cena's neck and skull.

But in typical Cena fashion, he fought through his pain and battled back. He was just about to level Snitsky with the FU, but Orton pounced on him. As Cena writhed and clutched his head, Orton gazed down on him, his teeth grinding and top lip quivering. The Legend Killer then grabbed the WWE Championship and stared at it longingly. Orton has one primary focus. He made history three years ago at SummerSlam, when he became the youngest World Heavyweight Champion ever, and is ready to make history again, even if it means ending John Cena's career. And no matter how much Cena tries to hide it, the third-generation Superstar knows The Champ is wounded and therefore vulnerable. (WATCH)

"He [Cena] may have suffered a mild concussion and probably hurt his neck," Rios said. "He hasn't been able to move as easily as he did before. He's going to know that he might hurt his neck, and he might not want to put full force on his neck. There's an advantage for Randy in hurting him and a disadvantage for John."

But don't expect anything less than 100 percent from Cena. The "Live Fast, Fight Hard," mantra on his T-shirts is not just a clever catchphrase; it's a way of life for him. Cena knows no other way, and has been overcoming all odds in his 11-month championship reign.

Still, after WWE officials examined him on Monday night, Cena decided not to comment on his condition. He winced slightly as he trudged out of the trainer's room, with his WWE Championship over his shoulder. Again, his eyes told the story: It looked like he was wondering whether The Champ would still be here after SummerSlam.

Check out Cena's new Beware of Dog t-shirt...