Shawne Merriman blames being 'too damn heavy' for 'American Ninja' fail

Carrying 260 pounds on your frame works well if you are an NFL linebacker but — as a competitor on the "American Ninja Warrior" obstacle-course — it's better to be a little guy. And nobody knows that better than former NFL star Shawne Merriman.

Merriman knows from experience. The oft-injured former San Diego Chargers and Buffalo Bills linebacker recently appeared on the show and started off strong only to fail when it came time to negotiate the trampoline obstacle. 

"260 don't work on trampolines," Merriman says ... "My weight made the trampoline touch the ground."

The fit Merriman actually dropped pounds before the show and put together a pretty solid — if not tentative — run before tumbling into the water.

Merriman says if he's invited back next year, he GUARANTEES he'll finish the course.