Zack Greinke may pitch in the American League, but he has a wealth of experience against the Colorado Rockies.

Greinke, who spent the first seven seasons of his 19-year career with Kansas City and returned to the Royals in the offseason, also spent plenty of time in the NL West and logged heavy innings against the Rockies.

He'll get another shot at Colorado when the Royals open a three-game weekend series in Denver on Friday night. Greinke (0-2, 2.67 ERA) will be opposed by left-hander Kyle Freeland (1-3, 3.94).

Kansas City is coming off 3-1 road loss to the Texas Rangers on Thursday night, while Colorado had a much-needed off day.

Despite his record, Greinke has been pitching well -- and efficiently. In a time when strikeouts account for nearly a third of all outs across baseball, Greinke has been throwing few pitches, striking out only 7.5 percent of the batters he has faced through his first six starts.

He has fanned just 10 batters in 33 2/3 innings, and in only two of his six starts has he struck out more than one.

"It's brilliant, that efficiency," Royals manager Mike Matheny said recently. "And he's going to be able to have some really efficient outings just because he's making quality pitches, and he's manipulating the ball to get minor movement from one pitch to the next.

"You're not going to see the same thing. It could be the exact same pitch, but it'll have different movement the second time you see it. He's just trying to miss the barrel. That's pitching. It's undervalued in our game."

Greinke could see his style get tested in the thin air of Coors Field, but he boasts some success against the Rockies, mostly from his days with the Arizona Diamondbacks, Los Angeles Dodgers and Milwaukee Brewers. He is 14-7 with a 3.53 ERA in 36 career games (35 starts) against Colorado, 5-1 with a 4.01 ERA in 14 games (13 starts) in Denver.

Freeland, a Denver native, has never pitched against Kansas City, but he will get a chance to help the Rockies wash away their just-completed 1-5 road trip. Colorado lost two of three in Arizona and then was swept in a three-game set by the San Francisco Giants.

Usually the Rockies' issues on the road are lack of pitching and hitting, and they were during the latest trip. The staff allowed 24 runs in the three games against the Giants, and the Colorado offense averaged just 2.2 runs during the six-game trek.

Another unexpected problem has cropped up this season for the Rockies -- defense. Colorado has consistently played good defense over the years (the 2007 team had a .989 fielding percentage, which set a major league record).

This season, however, the Rockies have committed 24 errors, and their .980 fielding percentage ranks among the bottom third of major league teams.

"We have to assess where we all are as a group, individually and as a group," infielder Ryan McMahon, who committed his sixth error on Wednesday, told MLB.com. "But then you have to move on from it because we have another ballgame in a couple of days. As a team, we take a lot of pride in defense. I do specifically, and it's eating at me a little bit. But I'll be good to go and I'll move past it in time for the next game."