10. Jeffery Hammonds - 2002: -0.5 WAR
When the Brewers signed Hammonds to a three year deal for north of $21 million, the hope was that he could put his history of injuries behind him and continue his offensive breakout from the previous season. Unfortunately, that did not happen as he missed significant time during his three seasons in Milwaukee. The one season where he did play most of the season, he posted a .729 OPS with bad defense, earning him the #10 spot on this list.
9. Prince Fielder - 2006: -0.7 WAR
You won't find much slander about Prince Fielder here as he was legitimately awesome for Milwaukee from 2007-2011 where he was a perennial MVP candidate while hitting bombs on the regular. However, his first full season in the big leagues was decidedly less awesome. Prince hadn't quite hit his full stride at the plate yet and with his defensive limitations, his overall production in 2006 despite a .271/.347/.483 line only totaled -0.7 rWAR. Still love you, Prince.
8. Orlando Arcia - 2019: -0.7 WAR
It can't be fun to see Orlando Arcia's name on this list considering how well he is playing for the Braves right now, but they did have some reason for skepticism with him. Case in point is his 2019 season where he slashed .223/.283/.350 in 546 plate appearances. Despite his pedigree as one of the best prospects in baseball beforehand, the Brewers decided to trade Arcia to Atlanta in 2021 and it certainly looks like he has figured things out much to the chagrin of Brewers fans.