Pretty much nothing, if you ask his private coach. George Whitfield, who has been working with Manziel for weeks in San Diego in preparation for the combine, appeared on "NFL AM" with a quarter-inch prop between his fingers, to illustrate the difference.
"America, this is it. The baddest football player on the planet, plus this, is six feet," he said.
Although NFL scouts take height very seriously in evaluating quarterbacks, it will be Manziel's ability to translate his unique scrambling skills to the NFL -- or, perhaps, learn to play without them -- that will ultimately be the determining factor in which NFL club invests its future in the former Heisman Trophy winner.
Whitfield insisted Manziel can be comfortable in an offensive system that calls for patience in the pocket.
"I think his ability, versus his style, are two different things. When things break down or when defenses overwhelm the pocket, he has a rare ability to equal that out. But he is just as capable as anybody else (of) playing in rhythm, be it a West Coast offense or a vertical system. I think he's excited about that challenge," Whitfield said. "I know the country will be excited to watch him play on Sundays. But he led college football in accuracy from the pocket this year, so it wasn't like he was just some Whirling Dervish all over the field. He's strong, he's accurate, and he's a winner. He can play in a systematic, regimented, pure progression system."
Manziel will not throw passes at the combine and will instead throw for scouts at his own pro day workout on March 27, about six weeks before the NFL draft. Whitfield said footwork has been a focus for Manziel in his workouts in San Diego.
"Like (former Whitfield pupils Cam) Newton and (Andrew) Luck at this phase, his footwork for coming out from under center. Just like all young quarterbacks, the NFL routes are going to be a little bit different from the collegiate routes," Whitfield said. "It's just what they're accustomed to doing, so we're going to have to familiarize him with some of those things."
Last week, Manziel essentially dared the Texans to pass on him with the No. 1 pick, saying it would be "the worst decision they've ever made."