Chris Carter
When the Yankees signed Chris Carter before the 2017 season, the hope was that he would be able to bring his prodigious power with him, as he had just led the National League in homers while playing for the Brewers. Sure, he struck out a lot and didn't hit for much of an average throughout his big league career, but that could have (probably) been forgiven if he was hitting dingers.
However, that did not happen, as he hit just eight homers in 62 games in pinstripes before the Yankees DFA'd him. Yankees fans turned on Carter quickly, as he was particularly horrendous when it came to striking out and playing in the field. It takes a special kind of bad to make it onto this sort of list in less than a season's work, but Carter pulled it off. The Yankees were sort of asking for this one, though, as everyone knew Carter was a strikeout machine with contact issues, including his former teams.
Kevin Brown
The Yankees acquired Kevin Brown in the twilight of his career in a trade with the Dodgers, and there were already some red flags prior to his arrival. Brown had a lengthy track record of being awesome on the mound, but injuries were already starting to pop up. Besides, the righty didn't have the best reputation when it came to getting along with his teammates over the course of his career.
Well, all of the bad came with Brown without much of the production, as he put up a 4.95 ERA in 35 starts with the team. He got so frustrated after one start that he punched concrete and predictably broke his hand, which caused him to miss a big chunk of the 2004 season. Brown returned for the playoffs and was on the mound when Boston torched the Yankees in Game 7 of the 2004 ALCS to complete the Red Sox' improbable comeback after New York had taken a 3-0 series lead. It is safe to say Brown is not missed in Yankees-land.
Kei Igawa
During one of the arms races between the Yankees and Red Sox back in 2007, New York decided to sign Kei Igawa out of Japan to a five year, $20 million contract after paying a $26 million posting fee just for the right to talk to him. This was a direct response to the Red Sox signing Daisuke Matsuzaka, but Igawa was pretty highly regarded himself, even though the track record of Japanese players finding success in MLB was spotty even back then.
Sadly, it was not to be, as the Yankees shelled out all that money for Igawa for 71.2 innings of work. From 2007 to 2008, Igawa put up a 6.66 ERA with an earned reputation of struggling to find the strike zone, especially in big spots. The Yankees held onto Igawa in the minor leagues until his contract expired, but he never appeared in the big leagues again after 2008 and returned to Japan, where the injury bug plagued him for a few more seasons before he hung it up.