Returned missionaries. Are these RMs so much far-and-away better than everyone else that the dominate the competition on their own team and are always starters?
You don't have to bring up honor code, recruiting pool, or anything else. The simple fact is that a mission is a net disadvantage for an athlete. The slight bump in maturity is grossly offset by other physical and health negatives.
The fact that even simpler minds can not understand this shows that some people more willingly grasp straws than concepts.