(Adam Hunger / USA Today)

Johnny Manziel’s future in the NFL won’t be determined by the number of trips he makes to Las Vegas or his proclamation that “I’m going to live life to the fullest.”

It’s going to depend on his size — specifically on his weight, not his height.

He may, as he has said, feel like he’s “10 feet tall” when he plays, but Manziel came in at just less than 6 feet when he was measured at the NFL scouting combine in February, failing to live up to his prediction that he’d be just over the line. Everyone knows that. But Benjamin Morris at FiveThirtyEight.com crunched the numbers and came to the conclusion that weight — Manziel weighs 207 — is undervalued as a predictor of success for quarterbacks.

[H]istorically NFL teams’ approach to undersized QBs has been not to draft them — if they’re short. My research suggests this strategy is insufficiently nuanced: If height matters at all, NFL teams have already accounted for that and then some. Being too light-weight, on the other hand, appears to be a stronger predictor of performance (or lack thereof), and NFL teams seem not to have accounted for it enough.

(Courtesy fivethirtyeight.com)

It makes sense, given that the trend across the NFL is toward heavier, bigger players. (Often to their detriment later in life.) However, Morris takes it further, factoring a player’s draft position into the equation.

Not only is height not a good predictor when combined with weight and pick location, it’s a slightly negative one (though to be a statistically significant negative predictor, we’d want to see values below -2.0). This doesn’t mean that height is bad, it just means that — whatever value it may have — NFL teams are likely overvaluing it.

Weight, however, is a highly significant predictor for these metrics.6 Since draft location is included as input for this regression, this strongly suggests that NFL teams have not been sufficiently pricing weight into their selections.

Earlier this year, Craig Booth, a data engineer at Narrative Science, used data from Pro Football Reference to show how the median weights of various positions, including quarterback, have changed since 1950.

(Courtesy Craig Booth)

(Courtesy Craig Booth)

Related: Life after being a 300-pound-plus NFL lineman isn’t easy