A matchup with Wandy Rodriguez seems unlikely to help.
Runs could be hard to come by against Houston on Friday night, as Rodriguez looks to continue his recent dominance over the Pirates while Paul Maholm tries to extend his home mastery of the Astros.
Pittsburgh (15-16) has averaged 2.9 runs at home, where it's hitting a major league-worst .199 and has gone 4-8.
Facing Rodriguez (1-3, 4.26 ERA), though, has spelled trouble of late for the Pirates. The left-hander has gone 3-0 with a 0.77 ERA in his last three starts versus Pittsburgh - all at home - with 28 strikeouts in 23 1-3 innings.
Minute Maid Park was also where Rodriguez turned in his best performance of the season Saturday against Milwaukee. He held the Brewers to seven hits over eight scoreless innings, though he didn't get the decision in a 2-1 win after Brandon Lyon(notes) blew a save.
Rodriguez had a 5.40 ERA in his first five starts.
Even if the Pirates struggle to score, their scheduled starter may be able to match Rodriguez. Maholm (1-4, 4.14) has gone 6-1 with a 1.52 ERA in his last seven home starts against Houston, and he gave up one run in 16 innings to win his two outings at PNC Park versus the Astros in 2010.
Maholm, who gave up four runs over seven innings of a 4-1 loss at Colorado on Saturday, has received one or no runs in four of his last five starts.
As it turns out, there could have been some good reason behind Brandon Lyon's struggles.
The day after Lyon blew his fourth save in eight chances, the Astros sent their closer back to Houston for an MRI exam. He was diagnosed with a partial tear of his right rotator cuff and biceps tendinitis.
Mark Melancon will move into the closer's role while Lyon is on the disabled list, a period that has not been determined yet.
Lyon's injury had been kept quiet while he worked on what the Astros acknowledged on Thursday was weakness in his shoulder and some inflammation in his biceps. After his third blown save in his last five opportunities, Lyon admitted privately to some strength issues, and the Astros sent him back.
"We've had some questions about whether the strength in there is exactly where it needs to be," manager Brad Mills said. "To get that fully addressed, we wanted to get an MRI and see exactly where it was."
According to the statistically oriented website Fangraphs.com, Lyon's average fastball velocity is down from 91.6 mph last year to 90.4 this season. Wednesday, when he gave up four hits and a walk, Lyon never threw a pitch harder than 90 mph.
"I'm sure it's all tied in together," Mills said. "But when you get in a situation where his shoulder is a little weak and maybe he doesn't have the strength in the shoulder and he starts compensating in other areas, that's one of the reasons we wanted to look at this MRI."
* RHP Mark Melancon is taking over temporarily as Astros closer after RHP Brandon Lyon was sent back to Houston to have an MRI taken on a weak right shoulder. Melancon entered Thursday's game 2-1 with a 1.72 ERA in 18 relief appearances. "He's been throwing the ball really well, and he has a high level of confidence in the way he's been throwing."
* LF Carlos Lee took batting practice Thursday for the first time since he suffered bruised ribs Sunday. He hopes to return to action during the weekend series at Pittsburgh.
* LF Jason Michaels will join Triple-A Oklahoma City for a rehab assignment on Saturday as he works his way back from a separated shoulder. Michaels took a successful round of batting practice on Thursday. He is eligible to come off the 15-day disabled list on May 10 for a home game against Cincinnati.
* RHP Jose Valdez averted the 10-day waiting period to be recalled from the minor leagues when he got the call as a result of RHP Brandon Lyon's injury. Valdez, who made his major league debut after 10 seasons in the minor leagues, gave up five runs in five innings in his first stint with the Astros, being sent down to make room for RHP Wilton Lopez.
* RHP Brett Myers tied his shortest outing in 40 starts as an Astro, going 5 2/3 innings and allowing six runs to the Cincinnati Reds. "I didn't feel real comfortable out there," Myers said. "I felt like everything I threw they knew it was coming. They probably didn't, but it just kind of felt that way. It's one of those days you want to forget, but you've got to go get them next time." His only other outing that didn't reach or eclipse the six-inning mark also came at Cincinnati.
* 2B Bill Hall ripped home plate umpire Tom Hallion and the state of umpiring in general after he was ejected following a seventh-inning strikeout. "It's amazing how umpires can get away with so much stuff and nothing happens to them," said Hall, who contended that Hallion missed two calls in the at-bat and cursed at him to get back in the batter's box. "It's all about them trying to get something on ESPN punching someone out. …"
By The Numbers: 11—Stolen bases for Jason Bourgeois after two steals Thursday put him in a tie for the National League lead despite starting only eight games all season.
Quote To Note: "Umpires are obviously not getting punished enough because they feel like they can go out there and 30,000 people are out there to see them when they're not. They're out there to watch us." —2B Bill Hall. on what he called a declining state of umpire relations in baseball.
* LF Carlos Lee (rib-cage contusion) was injured May 1, and he hasn't played since. He took batting practice May 5, and he hopes to return during the May 6-8 series at Pittsburgh.
* RHP Brandon Lyon (partial tear of right rotator cuff and biceps tendinitis) went on the 15-day disabled list May 5.
* INF Jeff Keppinger (left foot surgery in January 2011) went on the 15-day disabled list retroactive to March 22. He played his first game in extended spring training April 22.
* OF Jason Michaels (separated left shoulder) went on the 15-day disabled list retroactive to April 25. He is scheduled to begin a rehab assignment with Class AAA Oklahoma City on May 7.
* RHP Alberto Arias (sore right shoulder) went on the 15-day disabled list retroactive to March 22. He threw to live hitters at extended spring training for the first time April 10. Arias felt another impingement in his shoulder April 15.
* C Jason Castro (right knee surgery in March 2011) went on the 15-day disabled list retroactive to March 22. He is expected to miss most or all of the season.