PITTSBURGH -- With Gregory Polanco and Elias Díaz back in their lineup and the Majors’ ERA leader on the mound, the Pirates cruised into the seventh inning with a three-run lead. Then everything went south in a hurry.

The D-backs began their rally with a couple of bloops and finished it with a blast, jumping ahead of the Pirates with a seven-run seventh inning, before they piled on with four more runs in the eighth to hand the Bucs a 12-4 defeat on Monday night at PNC Park.

The Pirates’ clubhouse was quiet afterward not only because of the loss, but because they saw reliever Nick Burdi walk off the mound in the eighth inning holding his surgically repaired right arm.

“We’ve had our fair share of injuries already, so I think we’re all going to say a prayer for Nick tonight and be in his corner to pull him through,” manager Clint Hurdle said. “However, we all acknowledge the fact that we’re going to play a game tomorrow as well and we’ll need to get ready to do that at some point in time.”

Starter Joe Musgrove took the mound in the seventh having thrown only 85 pitches, but he walked leadoff man Wilmer Flores, then gave up a single to Nick Ahmed. Out went Musgrove, who entered the night with a 0.81 ERA, and in came reliever Kyle Crick. Catcher John Ryan Murphy immediately loaded the bases with a bunt single. Then things got a little weird.

Pinch-hitter Blake Swihart tapped a ball back toward the mound, and Crick raced in to field it. Crick flipped the ball to Diaz for the force out at home, but Diaz never stepped on the plate or tagged the runner. Swihart was credited with an RBI single, and the D-backs pulled within two runs.

“When I went to [field] the ball, I tried to jump back but I lost home plate,” Diaz said. “I thought my foot was on home plate, but it was like an inch from it.”

Jarrod Dyson, the next batter, hit another comebacker at Crick, whose throw home pulled Diaz off the plate, but the backstop managed to tag Ahmed for the first out. Eduardo Escobar then hit a bloop single into no-man’s-land in shallow left, dropping it behind third baseman Colin Moran and shortstop Cole Tucker. That cut Pittsburgh’s lead to one run.

“I think I executed that pitch pretty well,” Crick said. “Obviously not the result you want, but all you can do is get ’em next time.”

There was nothing cheap about the next hit, however, and it was probably the only pitch Crick would like back. David Peralta crushed a 1-0 fastball from Crick into the gap in right-center for a bases-clearing triple. Crick gave way to Burdi, but the rookie right-hander immediately gave up a two-run homer to Christian Walker.

Just like that, the D-backs had batted around and turned the Bucs’ 4-1 lead into an 8-4 deficit.

“It’s tough. It’s baseball,” Musgrove said. “It’s going to happen every now and again. You’ve just got to brush it off and get back to work.”

It only got worse in the eighth inning, when the D-backs put up four runs and the Pirates lost Burdi to an injury after he went down on the mound holding his right biceps. The night ended with outfielder JB Shuck on the mound, touching 91 mph in his second career pitching appearance.

Before the seventh, it had been shaping up to be an encouraging night for the Bucs. Polanco went 2-for-4 with a double and a walk in his return from the injured list. Diaz drove in a run in his season debut. Josh Bell continued to hit the ball hard, ripping a 110.9-mph triple to center for his 16th RBI of the season. Moran picked up a pair of hits and two more RBIs.

Some early missed opportunities came back to haunt the Pirates, however. They loaded the bases with one out in the first inning and didn’t score. In the second, Pittsburgh had two runners on with one out and didn’t score. The Bucs scored two runs in the fifth but once again left the bases loaded.