Marcos Alonso was the second-highest scoring defender last season, finishing one point behind teammate Gary Cahill despite playing 602 fewer minutes. The Chelsea defense was dominant once manager Antonio Conte inserted Alonso into the starting XI as part of his move to a 3-4-3 formation, and the former Fiorentina man's six goals in open play led all defenders (James Milner scored all seven of his goals from the penalty spot last season, and he was classified as a midfielder).
Alonso is now the highest-priced defender in the Premier League's official game, with three of his Chelsea teammates tying among nine players at the next price level. His success last season and price this year don't guarantee anything about this term, so we're obviously left with the question about who will be this year's top defender.
Many people immediately turned their attention to new Arsenal signing Sean Kolasinac, who is expected to play as a left wingback if Arsenal stick to their late-season three-man back line. Kolasiac played the role with Schalke in the Bundesliga last season, returning an impressive three goals, five assists and six clean sheets in fewer than 2,100 minutes. His clean sheet upside is certainly higher with the Gunners if he can stay on the field, and while goals and assists are the difference-makers for fantasy points in the league's official game, you still need a solid base of clean sheets (just ask Jan Vertonghen, assuming he always picks himself for his own fantasy team).
I understand the upside Kolasinac brings, but I'm planting my flag on Manchester City's Benjamin Mendy, who transferred from Monaco for the largest fee paid for a defender in history. Mendy is the very definition of an attacking fullback and now plays for a team that is the favorite to win the Premier League. He didn't score any Ligue 1 goals last season, but he had five assists and sent in 171 open-play crosses. No, you don't get fantasy points for crosses in the league's official game like you do on DraftKings, but sending in that many passes should lead to goals (I'll give those slapping their heads and screaming "Jesus Navas!!!" a minute to recover).
This isn't to say Alonso will be a bad fantasy option this season; in fact, I think he'll still be excellent. There are a number of very good attacking fullbacks in the Premier League, so much so that you could pick a team with them and get decent midfielder upside. Just like the forward and midfielder rankings, these are my preliminary thoughts on how the defenders will break down by the end of the season.