Colorado @ Arizona preview

Last Meeting ( Aug 9, 2014 ) Colorado 4, Arizona 14

The Arizona Diamondbacks try for their seventh straight victory over Colorado when they host the Rockies on Sunday in the finale of their three-game series. Arizona exploded for nine runs in the eighth inning - capped by rookie David Peralta's first career grand slam, which carried over the pool in right-center field - of Saturday's 14-4 win. Peralta finished with three hits and is batting .321 with five homers and 29 RBIs in 56 games as he continues to prove himself against major-league pitching.

The Rockies are 2-20 in their last 22 road games and fell to 5-15 since the All-Star break as their ERA rose to 5.03 - the worst in baseball. A bright spot for Colorado has been third baseman Nolan Arenado, who is 18-for-56 with four homers and 12 RBIs in 14 games since being benched for not hustling. Arizona's Wade Miley is 7-1 with a 3.20 ERA in 11 games against Colorado as he opposes Franklin Morales, whose last action was an unexpected relief appearance after five consecutive starts.

TV: 4:10 p.m. ET, ROOT (Colorado), FSN Arizona

PITCHING MATCHUP: Rockies LH Franklin Morales (5-6, 5.08 ERA) vs. Diamondbacks LH Wade Miley (7-8, 4.61)

Morales didn't factor in the decision as he allowed a run and two hits in three innings after Brett Anderson left in the fourth with back spasms in Colorado's 6-5 loss to the Chicago Cubs on Tuesday. The 28-year-old Venezuelan was 1-2 with a 3.38 ERA in his previous five games - all starts - and is 4-6 with a 5.30 ERA in 16 starts this season. All five of Morales' victories have come against the NL West - including an 8-5 triumph in Arizona on April 28, when he yielded four runs in five innings.

Miley was touched for a career-high 10 runs and nine hits in 4 2/3 innings of a 12-2 loss to Kansas City on Tuesday - his second setback in three starts. ''Everything I threw was in the middle of the plate,'' the 27-year-old Louisiana native told reporters. ''You can't find success up here when you are living in the middle of the plate.'' Miley, who pitched 6 2/3 scoreless frames to defeat Cincinnati in his previous turn, struggles with Carlos Gonzalez and Wilin Rosario (combined 16-for-37, two homers).

WALK-OFFS

1. Gonzalez, who is 8-for-51 with 20 strikeouts since the All-Star break, did not play Saturday after a recurrence of left knee tendinitis forced him to leave Friday's game.

2. Arizona's bullpen leads the National League with 389 strikeouts, trailing only the New York Yankees (414).

3. Colorado OF Charlie Blackmon, who is hitting .332 at home and .233 on the road, is 2-for-21 in five games at Chase Field this season and 13-for-25 against Arizona in six home contests.

PREDICTION: Diamondbacks 6, Rockies 2