Bill Swift
The best thing that Bill Swift did for the Rockies was help convey a sense of organizational legitimacy with his signing. Announced on the same day as the signing of Larry Walker (perhaps you’ve heard of him?), the fact that these two respected pros were choosing to come to Colorado helped the fledgling franchise establish itself as a legit major league organization.
While the club did make its first playoff appearance in ’95, Swift was hurt through much of the season. He then spent most of the next two years on the DL and was a shell of himself when he was out there.
Overall, Swift accumulated 1.5 WAR total in his time on the mound for Colorado. Those gains were hardly worth the $13M the Rockies paid Swift, though perhaps they helped establish themselves as a viable landing spot for big-name starters … for better or worse.
Howard Johnson
Signing former Mets outfielder Howard Johnson was one of the early offseason misses in team history. Only two seasons removed from a 38-homer All-Star campaign in 1991, HoJo signed for $1.7M but managed to hit only .211/.323/.405 across 269 plate appearances. This was worth a meager -0.7 WAR, but hey, at least it was just a one-year deal.
Daniel Murphy
It may not be totally fair to put a guy on this list after only one year, but right now the Daniel Murphy deal sure looks like a mistake. Last year Murphy made $10M last year for an 87 OPS+, -0.5 dWAR season that started with a month-long trip to the DL.
It’s possible that with a healthy offseason that the 35-year-old Murphy could have a better 2020. Perhaps he and Ian Desmond combine to form an effective platoon at first. Sure. It could happen.