Like any big dude in high school, the man who eventually became Braun Strowman could well have made himself a name in the American Football world. Coaches more than likely saw the oversized young man and immediately began to plot defensive strategies that revolved purely around him trucking his opponents, but strangely Strowman wasn't able to play much in the way of college football.
The reason is simple; his grades were not up to scratch. A country boy through and through, by Strowman's own admission he didn't put the effort into education that was properly required, and as such his poor performance meant that he wasn't given permission to take to the field. Strowman would eventually go to night school to improve his grades, which also meant him missing out on the wrestling team.
Strowman did eventually attend the NFL Scouting Combine but his lack of college football experience guaranteed he wasn't going to get picked up. He has also stated that he didn't quite have the mechanics for football, further proof that pure unadulterated strength isn't everything.