well, I believe the team does have coaches, who theoretically can look at the matchups and move players around.
in other words, if Fox winds up facing a brute who is muscling him, the coaches can make a substitution; change Fox's defensive assignment; or switch defenses (i.e. go from man-to-man to a zone....)
all of these things are - to the best of my knowledge - within the rules of the game.
so this idea that "Fox would get stuck in a bad matchup......" is - I humbly suggest - a bit of an overstatement.
any player can get stuck in a bad matchup. that doesn't mean that the team is unable to do anything about it.