Polanco's shot to the concourse in right-center field off Shelby Miller (1-6) in the first inning gave Pittsburgh an early boost. Francisco Liriano (4-3) scattered two hits in 5 2/3 innings and added an RBI single as the Pirates improved to 6-2 during a 10-game homestand.
After a short adjustment period, Polanco has thrived batting third in the lineup, hitting .317 (20 of 63) with three home runs and 13 RBI in 15 games. The Pirates spread their 17 hits among 11 batters.
Miller's recent recovery from a miserable start with the Diamondbacks took a step backward. Less than a year removed from an All-Star appearance with Atlanta, Miller's ERA ballooned to 7.09 after surrendering six runs in five innings.
The Diamondbacks acquired Miller in December figuring he and Zack Greinke could spearhead the club's return to contention. The transition for both has been uneasy at best. Greinke's ERA is 4.59 and Miller's remains well north of that thanks to an inability to keep the ball in the strike zone or the ballpark, problems that struck once again versus the surging Pirates.
Miller walked John Jaso to start the bottom of the first. McCutchen singled up the middle and Polanco drove the ball well over the fence to make it 3-0 before the Diamondbacks got their first out. Miller has now given up 10 home runs in 45 2/3 innings this season. He surrendered only 13 in 205 1/3 innings last season for Atlanta.
The Pirates piled on quickly. Jordy Mercer hit a two-run double in the third, and Liriano followed two batters later with a sharp single to left. The former outfielder is hitting .348 (8 for 23) with four RBI on the season.
Liriano tried to work quickly with the massive lead. The Diamondbacks didn't get a hit until Phil Gosselin's double leading off the fourth, at which point the Pirates were up 6-0. Liriano's command abandoned him briefly in the sixth, and he exited after walking in Gosselin with the bases loaded and two outs. Jared Hughes retired Brandon Drury to get out of the jam and Pittsburgh kept on going, scoring three in each of the sixth and seventh innings to improve to 15-2 in Liriano's last 17 starts at PNC Park.
Diamondbacks: 2B Jean Segura left in the top of the seventh after getting hit in the helmet by a 96 mph fastball from Pittsburgh reliever Arquimedes Caminero. Caminero was ejected after drilling Nick Ahmed in the eighth. ... OF David Peralta is hitting off a tee and sending manager Chip Hale texts about how rapidly his inflamed right wrist is improving. Peralta went on the disabled list on May 15. ... Reliever Josh Collmenter was scheduled to make a rehab appearance at Triple-A Reno. Collmenter has been on the disabled list all season with right shoulder inflammation.
Pirates: Pitcher Ryan Vogelsong has multiple facial fractures and significant swelling over his left eye after getting hit by a fastball from Colorado's Jordan Lyles on Monday. Vogelsong remained in the hospital on Tuesday and trainer Todd Tomczyk said it could be several days before the swelling subsides enough to get a clearer picture of the extent of Vogelsong's injuries, though Vogelsong's vision has not been severely affected. Pittsburgh called up A.J. Schugel to fill Vogelsong's spot on the roster.
Diamondbacks: Rubby De La Rosa (4-4, 3.53 ERA) returns to work on Wednesday after the Diamondbacks skipped his spot in the rotation while he dealt with a sore groin. De La Rosa is 3-1 with a 1.93 ERA in his last five starts.
Pirates: Jeff Locke (3-3, 4.63 ERA) looks for a second straight victory in the middle game of the three-game set. Locke is 0-2 with a 6.87 ERA in four career appearances against the Diamondbacks.