Yeah, that smells like desperation to have everything your team does look good. Greinke is 70-25 with a 2.94 ERA since leaving Kansas City.
Qualification for the ERA title since the beginning of 2011 would require ~730 innings (depends how many games the guy's team has played so far this season but 730-735 is about right). Amongst qualifying pitchers in that time frame, Greinke is 6th in ERA and he's thrown more innings than 3 of the 5 ahead of him. He's 9th in strikeouts and 4th in wins, and his 25 losses are 5 fewer than any other qualifying pitcher. This gives him the best W/L ratio of any Major League starter since being traded. He's at 2.8, and Scherzer and Kershaw are the only other pitchers above 2.
But yeah, let's call it one good season and protend Cain and Escobar are more valuable. Unless you think Wil Myers for Shields and Davis wasn't happening without Odorizzi, there's no way you can call this better than a push on pure player values. And frankly, with the minors depth the Royals had at the time, I wouldn't buy that argument.