Washington @ Colorado preview

Last Meeting ( Jul 8, 2012 ) Colorado 4, Washington 3

One year ago, the Colorado Rockies were 11 games under .500 en route to a franchise-worst 98-loss season. Not only are the Rockies 34-30 as they begin a three-game series with the visiting Washington Nationals on Tuesday, they are winning games in ways of which they seemed incapable last season. The latest example came Sunday, when Colorado rallied to tie the game with three runs in the bottom of the ninth before defeating the San Diego Padres 8-7 in 10 innings.

Washington is hitting .234 - fourth-worst in the major leagues - but broke out with 12 runs in a doubleheader sweep of Minnesota on Sunday. The Nationals' Dan Haren has not strung three quality starts together this season and was ineffective in his last outing. He will oppose Jhoulys Chacin, who has not won since April 19 while recording no-decisions in his last four turns.

TV: 8:40 p.m. ET, MASN 2 (Washington), ROOT Sports (Colorado)

PITCHING MATCHUP: Nationals RH Dan Haren (4-7, 5.45 ERA) vs. Rockies RH Jhoulys Chacin (3-3, 4.59)

Haren allowed five runs and seven hits over four innings in Washington's 10-1 loss to the New York Mets on Wednesday as his struggles continue. ''I feel bad for the guys, letting them down. I can't be this inconsistent,'' Haren said following the game. The 32-year-old, who is 5-2 with 53 strikeouts in 52 2/3 innings at Coors Field, has shut down Michael Cuddyer (4-for-27, 10 strikeouts), but Carlos Gonzalez (7-for-18, three homers) has been a tough out.

Chacin, who has a 6.43 ERA over his last seven starts (0-3), pitched four scoreless innings before yielding five runs and seven hits in 5 1/3 frames in Colorado's 6-5 loss in 12 innings to San Diego on Thursday. The 25-year-old's last quality start came three outings back in Houston, when he allowed two runs in seven frames and struck out a season-high nine in the Rockies' 3-2 loss in 12 innings. Chacin has struggled against Ryan Zimmerman (4-for-7, two home runs).

WALK-OFFS

1. Colorado CF Dexter Fowler, who was 8-for-16 and scored six runs in the final three games of the Padres series after sitting out the opener with a migraine, is hitting .304 - .344 at home and .255 on the road.

2. Washington 1B Chris Marrero was called up from Triple-A Syracuse as the 26th man Sunday and apparently will stay with the team as OF-1B Tyler Moore was sent down. Moore is hitting .158 in 95 at-bats after delivering 10 home runs in 156 at-bats as a rookie in 2012.

3. Cuddyer, who missed the final three games against San Diego with a left rib cage injury, is expected to return to the lineup Tuesday. He is hitting .339 with 10 homers and 39 RBIs.

PREDICTION: Rockies 6, Nationals 5