One of the most common mantras about the NFL is that the game is really "just a business."
Indeed, there are few real-world professions with shorter lifespans, where an individual can rise and fall with equal swiftness. Whereas most people in their late-30s are just ascending their fields, NFL players at that threshold are dinosaurs on the verge of extinction.
That's not to say that stars on the decline are no longer useful players. But when their legacy and past deeds begin to outweigh their present-day ability, the notion of retirement becomes an unavoidable suggestion.
All the players on this list are still potential contributors in 2014, and it's not a guarantee that next season will be their last. However, when considering age, playing ability and contract situation, these five players could be taking the field for the final time next year.