On July 20th, the Rockies traded Jeremy Guthrie to the Royals for Jonathan Sanchez. It wasn't so much a change-of-scenery trade as it was synchronized self-preservation, as if both teams' rosters reflexively rejected a toxic substance and instinctively sent it somewhere, anywhere else. The two starters' stats, before the trade:

Sanchez: 53 1/3 IP, 6.1 K/9, 7.4 BB/9, 7.76 ERA (-0.7 WARP)
Guthrie: 90 2/3 IP, 4.5 K/9, 3.1 BB/9, 6.35 ERA (-1.0 WARP)

And since the trade?

Sanchez: 11 1/3 IP, 7.1 K/9, 7.1, BB/9, 9.53 ERA (-0.2 WARP)
Guthrie: 31 1/3 IP, 7.5 K/9, 2.0 BB/9, 4.02 ERA (0.4 WARP)

In his last three starts for Kansas City, Guthrie has allowed three runs in 21 innings against three playoff contenders (the Rangers, White Sox, and A's), striking out 18 and walking four. As Matthew Pouliot points out, Guthrie has been considerably better than Zack Greinke, Ryan Dempster, Anibal Sanchez, and Francisco Liriano since switching teams, even though all four of those starters, unlike Guthrie, were traded for players who weren't actively sabotaging their teams.

In other news, I'm working on a theory about Coors Field being a tough place to pitch.