"We've been kind of limping through this for about 10 days now," manager John Russell said. "The bullpen has been extremely overused. The guys are giving what they have. There's just not much left in the tank."
With the loss, the Pirates finished their seven-game homestand 4-3 and head into the All-Star break with a 44-50 record. The Pirates' pitching staff has given up a National League-high 517 runs, while the Pirates' offense is in the top five, with 454.
"Obviously, we've scored a lot of runs," Russell said. "We need to pitch better. We haven't pitched the way we need to pitch to try to win games."
Sunday's victim was reliever Franquelis Osoria, who gave up four runs in a critical seventh inning after the Pirates took a 6-5 lead on Chris Gomez's two-run double in the sixth.
Osoria gave up RBI hits to third baseman Troy Glaus, outfielder Chris Duncan and catcher Yadier Molina. Osoria's slip up came a day after a scoreless two-thirds of an inning, when the right-hander was making his first appearance off the disabled list.
"He didn't have his sinker going," Russell said. "When he doesn't, the ball is up, out over the plate and they hit some balls really hard. He's got to get the ball moving down toward the dirt, and he didn't do that today."
Ian Snell's stat line suggested similar struggles, but his outing was actually a step forward for the Pirates' Opening Day starter.
At one point, Snell retired 11 batters in a row with a crisp fastball and slider. But with two outs in the fourth, the Cardinals figured out the right-hander's mix of pitches. Glaus and Duncan doubled to begin the two-out rally and Aaron Miles capped off the four-run inning with a three-run blast to right field.
"He swung out of his shoes," Snell said. "I didn't realize he had that much power."
Snell finished with a line of five innings, five hits, four runs and six strikeouts. He was also extremely efficient, throwing 64 of his 90 pitches for strikes.
"I felt really good," he said. "The fastball was good. [I was] hitting my spots. My mechanics were good. It's just one pitch. That one pitch got me."
Russell echoed Snell's evaluation saying, "He's definitely on the right track. Each start you can see what he's doing, and you just know he's going to get better."
"The three-run homer obviously really hurt him," Russell added. "His command is coming back. He's making pitches, but he's not quite where he needs to be. I liked the way he attacked the zone."
The Pirates tied the game in the fifth when Ryan Doumit hit a double, bringing in pinch-hitter Freddy Sanchez. Jason Bay followed one batter later with an RBI single to left field.
The Pirates took an early one-run lead in the first on Xavier Nady's RBI single up the middle.
All six of the Pirates' runs came against Cardinals starter Joel Pineiro, who was hit hard for 10 hits in 5 2/3 innings.