Capps came into Monday's contest, charged with trying to nail down a Pirates victory with the Bucs leading the Cubs, 10-8. After getting the first hitter he faced to fly out, Capps was struck in the elbow on a ball off the bat of Cubs catcher Geovany Soto.
Soto laced a line drive up the middle, giving Capps time for little else but to pull in his right arm to protect himself. The ball hit Capps squarely and ricocheted all the way to the Cubs' dugout for a single.
Capps, in obvious pain, immediately hunched down and walked off the mound toward the Pirates' dugout. He spoke just briefly with manager John Russell and one of the Pirates' trainer before making his way to the clubhouse, still visibly hurt.
"He had a lot of numbness and tingling right after he got hit," Russell said afterward. "He came up and was evaluated by the doctor. The numbness and tingling subsided. The range of motion was pretty good. He got the feeling back. He's on his way to get some X-rays and we'll know more after that."
Russell described the area where Capps was hit as "a little toward the triceps, but right on the elbow." It was not believed to be the same part of the elbow that was bruised earlier this month, causing Capps to miss a little less than a week.
The results of his X-rays will be known on Tuesday.
With Capps out, Russell hailed Sean Burnett from the Pirates' taxed bullpen to get the final two outs with little time to dwell on the magnitude of the situation.
"That's probably the best thing for me," Burnett said. "Anyone who knows me knows that when I start thinking, I'm in a lot of trouble. Unfortunate what happened [to Capps], but we still had to get two outs and win the game."
Burnett, who had been unable to convert a save opportunity in Washington last week, sandwiched a walk in between a strikeout and groundout to seal the win. It was his first career Major League save.
"I was already pretty loose from warming up the inning before," said Burnett, the sixth Pirates reliever of the night. "I knew I had to go make the best of it."
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.