There isn't a more amazing comeback story in football these days than D.J. Hayden's.

Some five months ago, the University of Houston cornerback, a guy whom some NFL scouts talked about as a possible first-round draft pick, almost died after a freak collision during football practice. He ended up tearing a major vein in his heart. Hayden had a five-percent chance of survival, doctors later told CBS.

A rupture of the inferior vena cava does damage to the main vein that carries blood from the lower half of the body to the heart. It is a condition that rarely occurs in anything other than horrific automobile accidents.

Thanks to expert work by the UH staff (which colleague Dennis Dodd covered in great detail here), Hayden became part of that very fortunate five percent. Doctors thought it would take a miracle for Hayden to have been able able to compete at the combine last month. But it was just as jaw-dropping that, on Monday, there was Hayden, starring at Houston's Pro Day with more than 25 NFL teams watching. Hayden wowed them -- not just with his recovery but also with his speed, clocking a 4.40 in the 40, reports NFL.com draft expert Gil Brandt, who said the 2011 Conference USA Defensive Newcomer of the Year exceeded expectations and is 100 percent healthy.  

"It was one of the most incredible things I've ever witnessed," said UH coach Tony Levine, who estimated Hayden has been back training for about six-to-eight weeks. "You should've seen the look on the faces of the scouts after they looked at their stopwatches. Priceless."