ST. LOUIS -- What Jeff Karstens did to stabilize the Pirates' rotation for months will not become inconsequential with a subpar finish. But he has hit a snag in August, a month in which Karstens had bookend starts lasting less than four innings.
Karstens labored through 3 2/3 frames in Sunday's series finale, which the Pirates dropped, 7-4, to the Cardinals at Busch Stadium. The Pirates lost three out of four games during their stop in St. Louis.
There were varying reports afterward about how much Karstens' right shoulder -- which cramped up on him at the end of his last start -- might have adversely affected his command in this one. Karstens called that cramp a "non-issue," adding that he didn't feel shoulder issues deserved any blame for his performance Sunday.
Manager Clint Hurdle had a bit of a different take.
"I think he fatigued much quicker today, for whatever reason," Hurdle said. "He wasn't as sharp as he's been throughout the start. I think he felt some tightness, a little discomfort [in the shoulder]. No pain, nothing like that. It just wasn't there for him today."
Hurdle left open the possibility that Karstens could get a breather by having a start skipped. Karstens is tentatively scheduled to pitch next on Friday in Chicago.
"We'll have to reevaluate," Hurdle said. "I'm going to have to wait and see how he feels [this week]."
Karstens took the mound Sunday already staked to a one-run lead. That advantage morphed into a two-run deficit by the time Karstens recorded his third out.
An infield groundout with the bases full and a pair of two-out singles plated three Cardinals runs. The Pirates grabbed the lead back in the second, only to watch Karstens give up a run in both the third and fourth innings. The Pirates never led again.
"Our offense gave me four runs," said Karstens, now 9-8 this season. "I should have made it work. I didn't. They hit some ground balls that found holes, but I've got to make better pitches than that. I really didn't make many good pitches today."
Karstens was taken out with a runner on third and two outs in the fourth. He gave up five runs, nine hits and two walks in all. It wasn't as rough as his 3 1/3-inning start against the Padres back on Aug. 5 -- Karstens gave up nine runs in that one -- but there was still little that resembled the pitcher who had been so dominant earlier in the summer.
Through June and July, Karstens pitched at least 6 2/3 innings in 10 of 11 starts. He did not allow more than three earned runs in any of those games. In comparison, Karstens lasted that long just once in five August outings. His ERA for the month stands at 7.46.
While no one is blaming the dip in effectiveness explicitly on fatigue, that could be an underlying issue. With a month still remaining, Karstens has already logged 152 innings. He pitched a combined 138 2/3 between Triple-A and the Majors all of last season.
The last time Karstens threw more than 152 innings in a year was 2006, and the majority of those came in the Minors.
Though Karstens said his body isn't telling him that fatigue is a problem, the Pirates will closely monitor the right-hander's work from here on out.
"When he tells us he's feeling good, we're trying to trust these guys to move forward and be smart with it," Hurdle said. "I think we'll definitely have to look at it with a more acute focus as we go forward."
The Pirates scored four times off Cardinals starter Kyle Lohse in the first two innings, but they couldn't keep the righty from earning his 100th career win.
Each of the first three Pirates hitters reached in the first, with Andrew McCutchen giving Pittsburgh a lead when he singled home Jose Tabata. The Pirates wasted an opportunity to add to that by then not taking advantage of having runners on the corners and no outs.
Ronny Cedeno drove home the first of three second-inning runs with a single. A throwing error opened the door for Pittsburgh to take a 4-3 lead.
From there, the Pirates' bats went silent. Lohse faced the minimum in his last three innings of the five-inning outing.
"I was watching him close," Cardinals manager Tony La Russa said of Lohse, who allowed eight runs to the Dodgers in his last start. "He had a totally different demeanor. He just kept competing. The other day was just one of those days. Today, he never gave the appearance that he wasn't able to get the next batter out."
Over the final seven innings, the Pirates had two hits, one walk and one hitter reach on an error. No one got so far as third base. In 14 innings this series, the Cardinals' bullpen allowed just one run.
Pirates reliever Chris Leroux had an impressive series of his own. With 2 1/3 scoreless innings on Sunday, he did not allow a run in five innings.
"Last year, I struggled in Triple-A and the big leagues," said Leroux, who returned from the disabled list last Monday. "This year, I pitched well in Triple-A, and I think that's really helped me succeed here. I also think the mechanical adjustments have made a big difference."
St. Louis padded its lead with two runs off Chris Resop in the seventh. The Pirates' bullpen was tagged for seven runs in the three losses to the Cardinals.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.