Colorado @ Arizona preview

Last Meeting ( Aug 29, 2011 ) Colorado 1, Arizona 5

THE STORY: The Arizona Diamondbacks are counting on a rookie to help extend their winning streak to eight games as Wade Miley takes the mound against the Colorado Rockies on Tuesday. Miley became the fifth Arizona pitcher to make his major-league debut when he started at Atlanta on Aug. 20. The Diamondbacks increased their lead over San Francisco in the National League West to five games with a 5-1 victory Monday over the Rockies, who have lost seven of nine on the road. Colorado's Carlos Gonzalez had his 15-game hitting streak halted in the series opener.

TV: 9:40 p.m. ET, Root Sports (Colorado), FSN (Arizona)

PITCHING MATCHUP: Rockies RH Aaron Cook (3-7, 5.47 ERA) vs. Diamondbacks LH Wade Miley (1-1, 4.50 ERA).

Cook managed to escape Wednesday's start against Houston with a no-decision after allowing six runs and 11 hits in five innings. The 32-year old has won just one of his last five outings and surrendered six runs in two of his last three. Cook is 6-4 in 21 career starts against the Diamondbacks, including a victory at Arizona on July 22.

Miley will be making his third career start. He notched his first major-league victory Thursday at Washington as he allowed five hits over six scoreless innings. The 24-year old began the season with Double-A Mobile before going 4-1 in eight starts with Triple-A Reno.

ABOUT THE DIAMONDBACKS (76-59): Arizona has allowed a total of six runs during its winning streak. The Diamondbacks also have won 10 straight games at Chase Field. Henry Blanco has been a thorn in Cook's side in their few meetings, going 3-for-5 with two home runs and four RBIs. Righthander Juan Gutierrez, who has been sidelined since May 24 with shoulder inflammation, will be on the shelf for quite a while longer. Gutierrez injured his elbow during a simulated game last week and needs Tommy John surgery. The 28-year old posted a 5.40 ERA in 20 games this season.

ABOUT THE ROCKIES (64-71): Gonzalez, who went 0-for-3 with a walk Monday, came within one game of matching the longest hitting streak of his career. He had a 16-game run from Aug. 23-Sept. 9 last year. Mark Ellis went 1-for-4 to stretch his hitting streak to a career-high seven contests. Colorado avoided being shut out when three different Arizona pitchers hit a batter in the ninth inning. Chris Iannetta was plunked by Diamondbacks closer J.J. Putz with the bases loaded to force in a run.

FINAL PITCH: Justin Upton became the third Diamondback to record 20 homers and 20 steals in the same season twice when he swiped his 20th base Monday. Upton, who also accomplished the feat in 2009, joined Eric Byrnes and Chris Young, who needs one blast and one steal to be the first player in Arizona history to become a three-time member of the 20-20 club.