Van Benschoten will be trying to lead the Pirates to a sweep of the last-place Houston Astros on Wednesday when the teams wrap up their three-game set at PNC Park.Van Benschoten (1-2, 10.64 ERA) owns the worst career ERA (9.04) in baseball history among pitchers with at least 75 innings of work. The right-hander, a first-round draft pick in 2001, is 1-10 with an 8.82 ERA in 16 career starts, with the lone win coming at home against Houston on Sept. 10, 2004.He lasted only 2 1-3 innings in a spot start last Wednesday, allowing five runs in Cincinnati. Still, the Pirates (42-47) are putting him in their rotation in place of Tom Gorzelanny, who was optioned to the minors on Saturday."John Van Benschoten's career track record has not been good," general manager Neal Huntington told the Pirates' official team Web site. "His last start certainly wasn't something that made you comfortable and confident. But his work to date has shown he has the ability. He just needs to go apply it."Five days before the start against the Astros (41-50), in which he allowed just one run in eight innings, Van Benschoten made his only other appearance against Houston, yielding six runs in 2 1-3 innings of relief and taking the 10-5 road loss.This time, he'll be trying to lead the Pirates to their fifth straight win over their division rival. Pittsburgh rallied for three runs in the eighth inning, capped by All-Star Nate McLouth's two-run single, en route to Tuesday's 4-3 victory.The game was slowed by two rain delays that totaled 3 hours and 7 minutes."It was a miserable night until the end there when we came out and won it," said McLouth, who also homered Tuesday. "It certainly makes it a lot easier to go home and go to sleep than it would have if we wouldn't have won."Now, the Pirates are on the verge of their first sweep of Houston since April 24-26 last season, when they took three games at home.Hunter Pence and Carlos Lee both homered Tuesday for the Astros, who have dropped seven of eight. Lee went 2-for-4 and is batting .426 (20-for-47) with four homers and 13 RBIs during an 11-game hitting streak.The Astros lost a 17-inning game Sunday in Atlanta and blew two leads in Monday's 10-7 loss to the Pirates. Their bullpen has pitched 19 2-3 innings the past three days."We've had three pretty long days," manager Cecil Cooper said. "It's been a little difficult for us."Houston will hand the ball to Brian Moehler (4-4, 4.13), who was pounded for five runs in six innings of Friday's 6-2 loss in Atlanta. In each of his previous three starts, the right-hander had allowed just one run."I'd get two strikes on a guy, get to 3-2 and walk him," Moehler said. "I just couldn't finish guys tonight. Just everything was up tonight. I didn't get the ball down tonight."Moehler is 3-4 with a 4.54 ERA in 10 career appearances -- seven starts -- against the Pirates.