The Pittsburgh Pirates, who are no strangers to close games, try for a three-game sweep when they host the struggling Colorado Rockies on Sunday. Pittsburgh prevailed 3-2 in 11 innings on Saturday and is 23-17 in one-run contests - 16-8 at home - with the wins and games leading the major leagues. More importantly, the Pirates are tied with Cincinnati - 2 1/2 games behind co-leaders Milwaukee and St. Louis in the National League Central - after improving to 11-2 in their last 13 at home.Colorado's season to forget took another bad turn as All-Star shortstop Troy Tulowitzki, who has 21 home runs and leads the majors with a .340 average, left Saturday's game with what the Rockies said was a cramp in the muscle of his left tensor fascia latae - or hip flexor. The Rockies are a major league-worst 16-32 on the road after wasting a second straight strong performance from a starter as Jorge De La Rosa (Friday) and Brett Anderson combined to yield two runs in 13 innings. Pittsburgh's Jeff Locke hasn't lost in six starts (2-0) as he opposes Tyler Matzek, who is 0-4 in six outings since winning his major-league debut.TV: 1:35 p.m. ET, ROOT (Colorado, Pittsburgh)PITCHING MATCHUP: Rockies LH Tyler Matzek (1-4, 4.97 ERA) vs. Pirates LH Jeff Locke (2-1, 2.89)Matzek, the 11th overall pick in the 2009 draft, lost his second straight start - a 9-3 setback to Minnesota on July 12 - after allowing four runs and seven hits in six innings. The 23-year-old California native has pitched at least six innings in his last four turns but permitted 12 runs in his last three outings. Matzek has performed better on the road - 0-1 with a 3.63 ERA in three starts - but has struggled during his two day outings, losing both while yielding nine runs in 11 1/3 frames.Locke recorded his seventh straight quality start, allowing three runs (one earned) and nine hits in 6 1/3 innings, but received a no-decision when the bullpen let him down in a 6-5 loss at Cincinnati on July 11. The 26-year-old New Hampshire native, who began 2014 on the disabled list with a strained oblique muscle, has been victimized by four blown saves in his eight turns this season. "I'm healthy and excited for the second half of the season," Locke told the Conway (N.H.) Daily Sun.WALK-OFFS1. Pittsburgh LF Starling Marte was hit in the head by a pitch Friday and did not play Saturday, while Colorado 1B Justin Morneau missed his second straight game because of neck stiffness.2. Pirates 2B Neil Walker recorded three hits Saturday, drove in a run and scored a pair - including the winning run on SS Jordy Mercer's one-out double.3. The Pirates are 11-4 versus the National League West, while the Rockies are 3-12 against the NL Central.PREDICTION: Pirates 3, Rockies 2