3) Brandon Nimmo
Every manager wants to put his best hitters at the top of the lineup, and Brandon Nimmo has always been one of the Mets' best hitters, which is why he's batted leadoff for most of his career. While Grimace got more than his share of the credit for the Mets turning things around this year though, the season was really kick-started around the time that Carlos Mendoza swapped Nimmo for Francisco Lindor in the leadoff spot.
That isn't to blame Nimmo for the way the Mets underperformed before then, as Lindor has unequivocally been the Mets' best hitter. What he can be blamed for is what he's done since then, which is close to nothing. Nimmo is batting well below the Mendoza line since the beginning of July, which coincides with the scary hotel room accident in which he fell unconscious during a late-night trip to the bathroom. He hasn't indicated that he's feeling any after-effects from that ordeal, but there has to be some explanation for the worst stretch of his career.
It's not like Nimmo has been sent to the bottom of the lineup. He's mostly hit second in the order, which shows how much faith Mendoza has in him. Unfortunately, he's rewarded that faith by giving the Mets close to nothing in well over a month, and the team is really feeling the effects.
Most Mets fans believed that Nimmo was snubbed from the All-Star team, and they had a point. With an OPS over .800, Nimmo was right there with the other top outfielders in the National League, but since then, he's fallen off the metaphorical cliff until a big home run on Friday out of the number three spot.
The Mets have done well to get themselves into contention after an ugly start to the season. If the playoffs are to become a reality, though, Alvarez, Severino, and Nimmo need to do their part. Nobody said it was going to be easy.