Guthrie, 33, has been nothing but a disappointment for Colorado. In his career before joining the Rockies, Guthrie had a career 4.19 ERA with a strikeout-to-walk ratio above 2 and a 47-65 W-L record. 2012 in Colorado has yielded a 6.35 ERA, a 3-9 record, and a 1.45 K:BB ratio.
There hasn't been just one thing to pin on Guthrie as to why he's been so bad. A lot of people predicted this performance, citing Guthrie's flyball tendencies, but if we were just discussing park effects, Guthrie's season would be a lot more excusable. But we've seen a decline in strikeout numbers, the ability to throw strikes, and by extension, a serious loss of the ability to pitch deep into games. Add in increased walk numbers and an increase in HR allowed, and Guthrie pretty much fell off of a cliff from the moment he arrived in Colorado.
In exchange, the Rockies will be receiving Jonathan Sanchez, a onetime exciting and intriguing southpaw with the Giants. Sanchez was traded to Kansas City for Melky Cabrera, and since joining the Royals has fallen off of a similar cliff. Sanchez' strikeout numbers have plummeted and his walk numbers have skyrocketed to the point where he has walked more batters than he has struck out this season. He's been more hittable than ever before, and his 7.76 ERA and WHIP above 2 attest to that.
That all said, Sanchez once drew Jorge De La Rosa comparisons from Rockies fans. When he's on, the guy has electric stuff, and would fall under the category of "effectively wild". There's no telling if the effective Sanchez will resurface ever again, but with a season that's all but officially over, it couldn't hurt.
Guthrie's contract this season is for $8.2M and Sanchez' is at $5.6M. No word yet on any money changing hands in this deal.