Could be one of those habit things athletes happen to do. An armchair QB watching from a recliner will recoil their fists to their chest, maybe be a pinky or two will be raised ever so daintily after a +20 yarder goes sailing, hoping it’s going to find the outstretched receiver.
Michael Jordan would hang his tongue out while focusing a layup. Can’t recall the nfl running back, but he would either snap on his chinstrap or let it dangle open at scrimmage, unintentionally telegraphing his role in the play.