3) Luis Torrens
He's no superstar, but in the absence of Francisco Alvarez, Luis Torrens has shown up for the Mets. Despite average surface-level stats, his Savant page has been blooming with red. He is in the 90th percentile of qualified hitters for xwOBA, the 96th percentile for xBA, the 90th percentile for xSLG, and his barrel rate and hard-hit rate are in the 94th and 95th percentile, respectively.
Besides, a .241/.279/.397 slashline is not too shabby for a backup catcher, and more than the Mets could've asked for out of a guy they got from the Yankees for cash considerations. It's important to note, as well, Torrens' success behind the dish. The Mets' pitching staff has thrived all year, and when Torrens is catching, they have an ERA of 2.36.
Alvarez, along with Jeff McNeil, is expected to be reinstated from the IL on Friday, meaning we'll see Torrens significantly less than we do now, but he has proven his worth in Alvarez's absence and is showing that he may even deserve to start somewhere. For now, the Mets have one of baseball's better backup catchers, and it's a bonus to add that they got him for basically nothing from their crosstown rivals last May.