There's actually some truth to that. They use the Wonderlic IQ exam to test incoming NFL players, and too high of a score is a detriment. There was an NFL punter in the 1970s who was a cum laude Harvard grad (U.S. history), and got a perfect Wonderlic score. He said that his high score hurt his position.

McInally claims it hurt, rather than enhanced, his position in the draft because "coaches and front-office guys don't like extremes one way or the other, but particularly not on the high side. I think they think guys who are intelligent will challenge authority too much."
https://en.wikipedia.org/wiki/Pat_Mc...onderlic_score