A troll would be a good football player, because they guard turf. The trolls' downfall is they're too much in conversation and not enough into actually eating their victims.
I'm thinking of the original story -- of which there are several national ones, if I have it right -- of the three billy goats gruff and the troll under the bridge. From this I get the message that trolls are more jealous of guarding their turf than they are of having an actual meal.
When it comes to eating, they're holding out for the biggest possible, which is just another way of saying turf guarding is also their obsession when it comes to meals. You figure they want the biggest portion but just to have a bigger portion than anyone; they can't eat it because then it'd be gone. Yet trolls have not wasted away from famine.
The first goat comes by, fine to eat as far as I'm concerned. But "You don't want to eat me. I am so small and bony. You should wait for my big brother. He is much meatier." The goat passeth over the bridge.
The second comes with the same reasoning. There's at least one bigger, meatier brother. But the third is not about to be eaten. You need to settle for one of the first two goats, and as for me, either one is as good as the other. I always prefer the first because the second is my insurance policy, my fallback. It's better to have and not need than to need and miss.