Guthrie, 33, was 3-9 with a 6.35 ERA in 19 games, including 15 starts, for the Rockies. He was 1-5 with a 9.50 ERA in nine games at Coors.
The Royals originally acquired Sanchez from the Giants for outfielder Melky Cabrera, who was a 2012 All-Star starter and earned the Most Valuable Player Award in the game. The Rockies sent pitchers Jason Hammel and Matt Lindstrom to the Orioles for Guthrie. Hammel was a Final Vote candidate for the All-Star Game.
The pitchers became, in the words of Rockies general manager Dan O'Dowd, "two guys that needed a change of scenery."
Sanchez went 38-46 with a 4.26 ERA in 174 games with the Giants, including 118 starts, before being traded to Kansas City. From 2009-11, Sanchez was 25-28 with a 3.75 ERA, with 484 strikeouts against 250 walks. His .204 opponents' average in 2009 led the Majors.
Sanchez will start for the Rockies on Monday night at Arizona, as he joins what will be all left-handed, four-man starting rotation. Sanchez will join Drew Pomeranz, Jeff Francis and Christian Friedrich. The Rockies were all-lefty for a brief period, when Guthrie was pitching out of the bullpen and Josh Outman, now at Triple-A Colorado Springs, was in the rotation.
Not to be overlooked is the fact Sanchez went 4-3 with a 4.76 ERA in 12 games -- including eight starts -- at Coors Field.
However, to be effective, Sanchez will have to curb a disturbing walk habit that has hampered his season: 44 walks against 36 strikeouts in 53 1/3 innings.
"If there is a next step that he can ascend, to take him to a different level, it's throwing more strikes than he has," Rockies manager Jim Tracy said. "It'll be interesting to see in relation to the format, how he gravitates to that."
Guthrie tweeted Friday: "Apparently I woke up as ROYALTY this morning. Disappointed w/how things went in CO. Optimistic for future."
Another tweet said: "Spoke w/both Dan O'Dowd & [Rockies owner, CEO] Dick Monfort. Expressed gratitude for their confidence in trading for me & lamented fact I didn't pitch better."
Said Tracy: "In fairness to Jeremy, I took a phone call earlier this afternoon where he pretty much was apologetic for the way that he had performed for our club. I'm bringing it up, because actually it's not something a player normally does. I think it's a show of how much he did care, how much he wanted to, but for whatever reason it didn't work out. For the good of him and the organization, you had to do something."