Carson Wentz
A little more a year after he missed the tail end of the 2017 season and watching Nick Foles lead the Eagles to the Super Bowl, Wentz received a four-year, $128 million extension that included $107 million guaranteed. Before he got hurt, Wentz looked like a serious MVP candidate in 2017, so you can’t fault the Eagles for giving him that much.
However, Wentz was just 5-6 the following year and dealt with a back injury, so it may have been a bad idea to give Wentz that much-guaranteed money. In his defense, Wentz was fine in 2019, but the wheels fell off after that. After he went 3-8-1 as a starter in 2020, leading the league in interceptions, the Eagles traded Wentz, who had failed stints in Indianapolis and Washington, all but ending his career as a starter in the NFL.