Give the New York Yankees credit: typically, they identify the right players to trade, even when it looks like they've thinned out their depth in some harmful way. Look at the Frankie Montas trade. Objectively, Montas as been a poor acquisition, but we'll let you Google Ken Waldichuk and JP Sears' early stats.
We don't have the heart.
In fact, the more common Yankees disorder involves pulling the plug too late on players rather than too soon. They sat on Miguel Andújar and Clint Frazier until both players had been significantly devalued; Frazier because of forces beyond his control, and Andújar because they didn't have the fortitude to get a deal done after his Rookie of the Year-esque 2018 season.
There are a few players over the past decade, though, who could've helped the Yankees, if only the team had properly evaluated them (or decided to get rid of Brooks Kriske at the right moment in history).
4 players the New York Yankees gave up on too soon
Jose Quintana, LHP
In the truest definition of this article's headline, the Yankees just ... gave up on Jose Quintana in the early stages of his development.
They didn't deal him for a failed veteran. They didn't toss him into a trade as an enticing fourth piece, only to later realize what they'd done. They just ... let him walk as a minor-league free agent. Free as a bird.
In 2011, he went 10–2 with a 2.91 ERA for the Tampa Yankees as a 22-year-old. That was his final act in pinstripes; he entered minor-league free agency following the season, and two White Sox scouts who liked what they saw in the Florida State League tapped their GM on the shoulder until he acted. Wisely.
He made his MLB debut that very same season, tossing 5.2 innings of shutout relief as the 26th man on a doubleheader's roster. That's right. The same left-hander who dominated A-ball in 2011 tamed big-league hitters in 2012, but the Yankees didn't see the correlation.
Quintana threw 200+ innings in each of the next four seasons, making the All-Star team and finishing 10th in the Cy Young chase in 2016. At the same time, the Yankees were running out patchwork rotation pieces from Freddy Garcia to David Phelps. What could've been.