Martín Pérez, LHP
You may not want Martín Pérez taking the ball in the season's most important series, and his cameo in the 2023 World Series didn't exactly earn him a ring. But steadiness is the name of the left-hander's game, even if he isn't likely to repeat his All-Star 2022 season.
Yankee fans might want to aim higher, but you'd be foolish not to prep for a sixth starter who isn't named "Uhh, Who Started in Scranton Five Days Ago???" The worst-case in adding the 32-year-old Pérez is that he remains a ~4.40 ERA pitcher who absorbs innings in blowouts as he attempts to transition into a potential left-handed relief role for the final years of his career. The best-case? He soaks up 150 innings and turns the fifth turn in the rotation from a mysterious cesspool into something that's taken care of.
Pérez is a regular-season addition rather than a postseason option, but failing to plan is planning to fail, and there's 100% chance the lefty's number gets called if the Yankees sign him, even if they squeeze him out of the rotation and towards the bottom of the depth chart before Opening Day.