Colorado @ Washington preview

Last Meeting ( Jul 1, 2014 ) Colorado 1, Washington 7

There is one simple explanation as to why the Washington Nationals on Wednesday can finish a three-game sweep against the visiting Colorado Rockies - they pitch better. Washington prevailed 7-1 on Tuesday and has outscored Colorado 14-4 in the first two games of the series while lowering its major league-best ERA to 3.04. The Rockies, meanwhile, have lost 13 of their last 15 games - including eight of nine on the road - while their ERA rose to 4.99 - the worst in baseball.

The Nationals on Tuesday had their Opening Day lineup intact in consecutive games for the first time this season and won their fourth straight contest to remain one-half game behind Atlanta in the National League East. Jayson Werth, who was 7-for-52 in his previous 13 games, went 2-for-3 with three RBIs, two runs scored and two walks. Washington's Doug Fister puts his perfect home record on the line when he opposes rookie Tyler Matzek, who is coming off a strong performance in Milwaukee.

TV: 6:05 p.m. ET, ROOT (Colorado), MASN (Washington)

PITCHING MATCHUP: Rockies LH Tyler Matzek (1-2, 4.24 ERA) vs. Nationals RH Doug Fister (6-2, 2.83)

Matzek received a no-decision after yielding one run and five hits while not walking a batter in six innings of Colorado's 3-2 loss at Milwaukee on Sunday. "He was really good against an all-right-handed lineup that is very good," Rockies manager Walt Weiss told the Denver Post after the 23-year-old California native's performance against the NL's top team. "It's very encouraging. Tyler is showing up very well. He's a guy who can help us moving forward here." Matzek was coming off back-to-back losses, allowing eight runs in 10 1/3 innings, after striking out seven in seven frames of an 8-2 win over Atlanta on June 11 in his major-league debut.

Fister received a no-decision after yielding three runs and seven hits while laboring through six innings in Washington's 5-3 loss to the Cubs in Chicago on Saturday. “(The Cubs) battled well,” Fister told reporters. “I didn’t execute a couple pitches, got them out over the middle of the plate, up in the zone, whatever it may be, and they capitalized on them. ... It’s just a matter of going out and getting it done. Five days from now, we’ll go back out and get it done.” Fister, who was 3-1 with a 2.38 ERA in June, is 4-0 with a 1.93 ERA, 0.79 WHIP and .192 batting average against in four home starts during his first season with the Nationals.

WALK-OFFS

1. Rockies SS Troy Tulowitzki, who leads the majors with a .353 batting average, was given Tuesday off by Weiss.

2. Washington LF Bryce Harper on Tuesday went 1-for-5 with three strikeouts in his second game since missing 57 contests because of a thumb injury.

3. Colorado has allowed four or more runs in 17 of its last 18 games.

PREDICTION: Nationals 6, Rockies 2