As a tide-you-over, let's take a moment to appreciate the fact that neither Mitch Boggs nor Ty Wigginton are Cardinals.
The reasons why Ty Wigginton is no longer a Cardinal are just as plainly evident as they were when he signed what was not the worst, but probably the strangest deal of the offseason. Signing Ty Wigginton to a minor league or league-minimum deal would have made sense, sort of, or at least represent the kind of plausible hope-superseding-experience thought process one could appreciate if not share.
Signing Ty Wigginton to a 2-year, $5 million deal made sense in no terms that I can understand. Wigginton was nominally signed as a right-handed slugger, even though he hasn't had a wRC+ over 100 since 2008 and he hasn't been better than replacement value since then either. Lauded for his positional flexibility, he was simply terrible defensively, wherever he stood. He has been worth -1.2, 0.0, 0.0, -0.8, and now -0.6 across four and a half seasons. It was no surprise that he was worse than useless for the Cardinals, at least not to much of anyone who wasn't signing his checks.
Mitch Boggs was much more perplexing. He'd come off a 2012 where he looked very sharp, albeit in large part by some deceptive outcomes. Boggs had a 2.21 ERA in 2012 that did not at all match his middling 3.68 xFIP.
His setup work in 2012 left him the default candidate to close in the wake of Jason Motte's elbow injury. He wasted little time in frittering away that opportunity in 2013. Boggs blew three saves in five chances, ran up an 11.05 ERA and walked more than a batter an inning. He did not have much luck regaining his command after he was finally, mercifully banished to Memphis. His walk rate dropped, but not to any kind of acceptable level for major league competition.
By some measures, Boggs rivaled Jorge Rondon and Maikel Cleto for the worst pitcher in the Memphis bullpen. Given the relative crowd of pitching prospects, Boggs' likelihood of rejoining the MLB team as an effective MLB pitcher this season was increasingly approaching zero. As he is well into his arbitration years, the Cardinals were unlikely to pay him millions of dollars to return in 2014 to try again. He was effectively done as a Cardinal.
So, what happened? Well, the loss of control was probably the most concerning thing. That could mean that Boggs is harboring some kind of injury. That could mean that Boggs was losing his stuff and overthrowing to make up for lost velocity. If he did, it was only partially effective; his 94.5 mph fastball in 2013 was already a substantial drop from his 95.8 mph last year and 95.2 in 2011.
Another curious factor to consider: Boggs' power sinker never resulted in the kind of strikeout rates you might expect from such a pitch, but he made up for it with above-average groundball rates, regularly hovering around 52% per fangraphs. His groundball rate dropped a few points this spring in the majors, but, stunningly, his groundball rate fell below average at Memphis, down to a 38% rate (compared to a 44% league average). That is . . . not a good sign of things to come.
We don't really know what happened. But there's very little reason to hold on to a 29-year-old reliever who's struggling to find the plate when lots of other hungry young pitchers are lining up to take innings. There's a nonzero chance that, with a fresh start in a new club, he'll succeed. The Rockies clearly think he's a bit of a project; the trade resulted in a further demotion to the Rockies AA farm team.
I hope that both Colorado and Boggs benefit from this chance, except when they're playing the Cardinals. I compared Boggs earlier to another promising Cardinal pitcher sent to Colorado for a bit of fresh air, Adam Ottavino. After five seasons of trying to find the plate unsuccessfully, Ottavino found it in the Rockies org. Although, Adam was several years younger than Boggs is now and transitioning from starting to relieving. But! The Point! Mitch could do better and I hope he does and I'm glad he's doing it somewhere not affiliated with St. Louis.