Dan Graziano says he believes the Vikings might have signed Kyler Murray to bring the best out of J.J. McCarthy, rather than to make Murray the starter. (1:39) In a perfect world, your favorite NFL team would keep everybody they want on a reasonable salary, add the best players available in free agency and find a sleeper or two on the lower ends of the market. In reality, of course, things rarely go that way. Most teams might be able to get deals done to keep their essential players around, but the salary cap ensures that even the best-run teams can't pay everyone. Organizations budget a certain amount of money for a player and then have to bow out once things get beyond their expectations. A market that containing, say, five viable young options at a position could dry up in a matter of hours, and the teams that didn't land their preferred choices have to try to find a replacement from whomever is left.…