It's more a case of decision making under pressure as a punt returner.

As a full-back in league, you're pretty much expected to at least make an effort to catch everything that comes your way. You can almost operate on instinct the minute a ball goes in the air.

As an NFL punt returner you can choose to either catch the ball and return it, call for a "fair catch" which means the opposition can't hit you but you can't return the ball, or just let the ball go altogether if you think it's going into the endzone (which results in you getting the ball back on your 20m line).

You've got to do all that in about four seconds between the ball leaving the punter's foot and arriving at you, while scanning the chase bearing down on you and remembering the fundamentals of catching the thing in the first place. Get it wrong, and you're horribly exposed. Get it wrong and turn the ball over as a result, and as Gareth says you're likely unemployed pretty quickly.

It's not unknown for players to come from other sports and make it in the NFL. A number of good kickers have come from a football background, Reinaldo Nehemiah went from being an Olympic hurdler to an NFL wide receiver, Darren Fells at Arizona was a pro basketball player for four years before coming into the NFL. In skill positions though, it's a really small number which gives you an idea of the difficulty of Hayne's task.

Hayne's a spare body at very little cost. He was put on the waiver and nobody came in for him - hardly suggestive that the 49rs or any other team sees much in him at all.

I'd say his mistakes have been really bad from a coaches perspective - dropping the ball is bad enough, but doing it by going for kicks that a college player wouldn't go near is a real coach killer. Add to that his complete failure to read a blitz and dropping the ball under bog standard contact on a running play and its not hard to understand why he won't get picked unless the 49rs run out of bodies.

I'm yet to see any evidence for Hayne's trip benefitting RL at all. I can well see him having another dig via training camps next year, and the pattern very much following this season, or failing to even get a squad place. If that happens then the 'benefit' to RL will be one of the best players in the game missing two years of his prime years. Even if Hayne becomes an unlikely success then he's the only winner.