While Ryan Dempster has pitched well in a Boston uniform, he doesn't have much to show for it.

He's always had trouble getting wins against the Houston Astros .

Dempster faces a familiar foe Friday night as the Red Sox continue a four-game set against the slumping Astros at Fenway Park.

Signed to a two-year deal as a free agent this offseason, Dempster (0-2, 3.38 ERA) has limited opponents to a .186 average and is among the AL leaders with 33 strikeouts through four starts. He allowed four runs and six hits over seven innings Sunday in a 4-2 loss to Kansas City.

"I thought he pitched with equal effectiveness, as he has in previous starts this season," manager John Farrell told MLB's official website.

One reason Dempster remains winless is that Boston (15-7) has scored just seven runs in his 24 innings. It's a similar start to last season, when Dempster was 0-3 after his first nine starts as the Cubs provided him 15 runs of support.

After spending the majority of his career in the NL, Dempster has plenty of experience against the Astros, who joined the AL this season. The 35-year-old right-hander is 6-12 with a 4.32 ERA over 51 games - 25 starts - versus Houston, tied for his second-most losses against any opponent.

Dempster, though, would appear to have a favorable matchup this time. Houston has lost six consecutive road games, getting limited to 17 runs and a .217 average after losing Thursday's series opener 7-2.

Carlos Pena is mired in a 1-for-20 slump for the Astros (7-15), who are looking to avoid their worst start through 23 games since 1969.

"It's definitely not fun," manager Bo Porter said.

David Ortiz went 3 for 4 with a homer and two RBIs on Thursday, remaining a difficult out since coming off the disabled list Saturday. He's 11 for 20 with six runs scored and five RBIs in five games after being sidelined with an Achilles problem which caused him to miss most of the second half of last season.

"It's remarkable the timing that he's displayed, particularly after the layoff that he's had," Farrell said. "I think even guys in the dugout are marveling at what he's been able to do, as far as not only contact but driving the baseball."

Boston, which improved to 11-0 when scoring first, went 6 for 12 with runners in scoring position. The Red Sox have gone 39 for 118 (.331) in such situations while winning 10 of 13.

Boston will try to stay hot against Erik Bedard (0-1, 6.17), who has not gone past the fourth inning in any of his three starts. The veteran left-hander pitched four Sunday and threw a season-high 75 pitches, giving up two runs and six hits with eight strikeouts in a 5-4 loss to Cleveland.

"Erik has some injury history and we're going to do everything we can to make sure we monitor his workload and continue to build him up going forward," Porter said.

Bedard, who spent part of the 2011 season with Boston, hasn't faced the Red Sox since 2008. He's 4-1 with a 2.22 ERA over his last seven starts against them.

Bedard has made things difficult on several of Boston's top hitters, including Dustin Pedroia (1 for 14), Mike Napoli (3 for 15) and Ortiz (5 for 24). Napoli and Ortiz, though, have combined for three homers against him.

Red Sox right fielder Shane Victorino is unlikely to be available after sitting out Thursday due to a stiff lower back. Victorino is batting .292 with 12 runs scored.

Boston has won four straight and eight of 10 all-time matchups against Houston, including all four at Fenway.

© 2012 STATS LLC