Josh Allen
This is the easiest and most obvious choice, as the Buffalo Bills will only go as far as their superstar quarterback can take them. Fortunately, Allen is more than capable of carrying this team all the way and he's a clear NFL MVP candidate too. The Bills will need Allen to continue to play at an MVP level all season with the defense being depleted with injuries.
I think it's too much to ask the Bills defense to keep teams, particularly the elite teams of the conference down on the scoreboard. So, it will be up to Josh Allen to lead the Bills' offense to points and keep the pressure on the opposing offenses to try to keep pace.
Allen is top five in the league in completion percentage, passing yards, touchdowns, QBR, and passer rating. He's number one in both completion rate and QBR. If Allen keeps up these numbers and the Bills put up wins en route to the playoffs, he'll be the NFL MVP.