The bullpen only added to that damage in the ninth, preventing a late rally and memorable day for Todd Helton from salvaging a victory.
"I think particularly with the time he's missed the last couple years, this is a heavy workload for him," Rockies manager Walt Weiss said about Nicasio. "But hopefully he's building up some strength as we move forward here, going into next season."
The club's second consecutive loss pushed the Rockies to 3-4 on their final homestand. They start a two-game set against the Red Sox Tuesday that will close their home schedule and mark Helton's final game at Coors Field.
Nicasio found himself in the jams he's had trouble escaping when D-backs second baseman Aaron Hill opened the second inning with a single and Miguel Montero walked, leaving runners on first and second with no outs. That was the impetus for the D-backs' four-run second.
Nicasio wasn't on the mound much longer, pitching just 2 1/3 innings and giving up seven runs allowed in one of his roughest starts of the season. It was another step back for Nicasio, who allowed eight runs over 2 2/3 innings in Tuesday's loss to the Cardinals, and owns an unsavory 9.56 ERA in September.
After a seamless first, Nicasio's day unraveled in the second. Gerardo Parra and Chris Owings ripped back-to-back doubles for a 3-0 lead and Adam Eaton's bunt single ended the inning when he was thrown out trying for second, but not before Owings crossed home plate.
In the third, D-backs drove in two more runs before Weiss made a trip to the mound. Reliever Jeff Francis served up an RBI single to Parra to hand Arizona a 7-0 lead.
"It's no excuse, but it's a long season and everybody's tired," Nicasio said. "I tried my best stuff today, tried to work hard and [you can't] make it happen sometimes."
But a bulk of the 43,736 fans in attendance came to see the final days of franchise icon Helton. He gave them a show worth watching, finishing 3-for-5 with two doubles that toed the line -- his signature hit and the 53rd multi-double game of his career -- and four RBIs.
"Good crowd, got to see Todd do things he's been doing for 17 seasons," Weiss said. "It's great to see him finishing with a bang. He's played really well, swinging the bat really well on this homestand. I'm happy for him, I'm happy for our fans getting to see that."
He sparked the Rockies ninth-inning surge by splashing a two-run single into shallow left. Yorvit Torrealba, pinch-hitter Jordan Pacheco and Charlie Blackmon followed with three singles to score two more, but it still left them four runs short thanks to a sloppy performance by the bullpen.
Starter-turned-reliever Chad Bettis served up a three-run homer to third baseman Matt Davidson, part of Arizona's five-run ninth.
"Just tried to keep a good approach and not try to do too much and he just hung a slider and I got it up in the elevation," Davidson said.
Helton's second double came in the fifth and crawled into the right-field corner, driving in Troy Tulowitzki and Charlie Culberson to cut Arizona's lead to 7-3.
Those two runs gave him 1,400 career RBIs, the crowd offering another standing ovation in recognition of his latest achievement.
Helton's three hits also pushed him into a tie with his former manager, Buddy Bell, for 95th on the all-time hits list. He will leave the game just as he imagined -- not as a veteran extolling advice on the bench but as a still-dangerous piece of the lineup.
"I've always said, when I die, I want to be scarred up and live my life to the fullest," said Helton, who's riding a five-game hitting streak. "I never said I wanted to retire like that. It's good knowing that I can go out and be productive and help the team every once in awhile."
Helton was the last batter D-backs starter Patrick Corbin faced. The young left-hander gave up 10 hits and four runs over 4 1/3 innings, striking out three and walking two.
Michael Cuddyer finished 3-for-5 to raise his batting average to .334, retaking the league lead. After missing three games with an injured wrist, Cuddyer dropped a single into right-center in the third for the Rockies' first run. In the fourth, Torrealba smacked an RBI single through the infield dirt to score Helton after his first double, trimming Arizona's lead to five.