Since roughly 2009 the Twins have had some well... rough seasons. When a team is bad, they become sellers at the deadline, and at least me personally, stop caring as much about the active games, and switch to focusing on prospects and the future.
During those bad years I become pretty fixated on prospects, so lets go over some that I really thought were gonna be good.
1. RHP Dakota Chalmers
Woof. I was so high on this guy when we acquired him from Oakland for Fernando Rodney in 2018. I blame Garvin Alston, the Twins pitching coach at the time, for talking up Dakota from his time coaching in the A's minor league system. I can't quite remember what he said but I'm almost certain he called him a "potential system changing arm" and I was hooked. Chalmers had a myriad of injuries as well as off the field mental health stuff that lead to him not pitching a whole lot before coming to the Twins, but once he did he had success. In 2019 he even pitched in the AA playoffs, and everyone seemed to be talking about his stuff, I was so intrigued. He was added to the 40 man roster in 2021 and I envisioned all his success, and it was followed by struggles and a pretty quick DFA. I was devastated. Since then he has been on a few different teams with little success, and is currently in the Dodgers system.
2. RHP Fernando Romero
Most Twins fans will probably remember this one, and probably at some point felt the same I did. A top arm in the Twins system for years, what wasn't to like about him. A fastball that reached 100 mph (This was pre Graterol and Duran so the Twins just frankly never saw that) and a wipeout slider to boot. We all remember his electric 2018 rookie season, where he had immediate success. He did drop off slightly as the year went on but still, the sky was the limit. That was followed by a ton of control issues in 2019 and after the season, he was out of the MLB completely (Although he potentially had a chance to re establish himself in 2020, but it was stopped completely by Visa issues. Because well... there were some things going on in the world that made it tough to travel) He is currently pitching in Japan.
3. OF Adam Brett Walker
This one was more me just being young and naïve more than anything. ABW was a 3 true outcome guy before it was cool. High power, high strikeout, and not a whole lot else. I really had no reason to be high on him besides the fact he had some really exciting homeruns. Wow could he hit the ball when he connected. He really was never much of a true prospect and never even got added to the 40 man in a Twins uniform. His last year with the Twins was in 2016, he bounced around the league until 2018. He then moved to indy ball, and actually some some success as recent as 2021, but it never materialized into a second MLB chance. He's currently playing in Japan.
4. OF Oswaldo Arcia
Much like Romero, I feel like most fans will remember this name. Arcia was an international FA signed in 2008, who quickly worked his way up through the levels and had a TON of success at each level. He reached the majors in 2013 and had some initial success, but really couldn't put together any consistency year-to-year. from 2013-2016 he was basically on the Twins taxi squad going up and down multiple times a year. The Twins eventually gave up on waiting and traded him to the Rays, but that didn't last very long. Altogether he was on 4 total teams (TBR, SDP, MIA, MIN) in 2016 but really had no success with any of them. In 2017 he had somewhat of a renaissance in the DBacks system, but I don't think anything could've happened to get him up with the team. Arcia was pretty much the definition of a AAAA player. He is currently playing in an Independent league.
5. RHP Alex Wimmers
I don't really have an explanation on this one. He was a first round pick I suppose so that always makes you hope they work out. Wimmers had a 22 game cup of coffee from 2016-2017 and had very mediocre results. in 2018 he struggled at AAA and was released. He had a short stint that year with Miami but registered no official playing time. He is currently not playing baseball anywhere.
Some of these are more defensible than others, but I just wanted to talk about them.