Mark Redman, also a vagabond veteran who has spent most of the season in Triple-A Colorado Springs, was designated for assignment after continuing to struggle.
The move reaffirmed what Rusch already knew: There's no longer any margin for error.
"Being older guys who have been around the block, we have to go out and produce," Rusch said. "But you can't think about that when you're out there. You just have to do your best."
Rusch (2-1) has been at his best for two straight outings. After giving up just one run against Milwaukee last week, Rusch stayed ahead in the count against Pittsburgh and used an array of offspeed pitches to keep them guessing. In 5 2/3 innings, Rusch gave up just two runs on six hits.
"Those are two good starts," Rockies manager Clint Hurdle said. "He's establishing some momentum off the mound and in the rotation for himself."
Rusch gave up a solo home run to Jose Bautista in the third, but that was his only blemish until he ran into trouble in the sixth. He gave up a run and left runners on the corners, but Jason Grilli came in and cleaned up the mess by striking out Jason Michaels to end the inning.
Colorado closer Brian Fuentes, who has been the center of trade talk recently, retired the side in the ninth to pick up his 16th save of the season. He has retired 21 straight batters and is one save shy of the Rockies' all-time record of 102 by Jose Jimenez.
After the game, Hurdle was quick to remind the media that there's no "For Sale" sign hanging in front of Fuentes' locker.
"And at the end of the day, we don't have to trade him," Hurdle said. "I think that's a point people miss."
The Rockies' offense celebrated its resurgence by tallying three home runs against the Pirates. But the most impressive homer was the one that never cleared the fence.
With the Rockies up, 4-2, in the seventh, Seth Smith pinch-hit for Grilli and belted the first pitch he saw into right-center field. The ball smashed against the bottom of the fence and rolled 40 yards to left-center, enabling Smith to chug home for his first career inside-the-park home run.
"That's a snagglepuss that nobody can anticipate," Hurdle said. "This was the most extreme carom I have ever seen."
The inside-the-parker was the 11th in Rockies history and the second this season. Jeff Baker accomplished the feat on June 17 against the Indians.
Like Baker, Smith was running on fumes as he dashed to the plate.
"There's no telling what my body would do if I tried to slide at that point," Smith said. "But it was great."
Matt Holliday hit a two-run home run in the first to give the Rockies an early lead, and Brad Hawpe blasted a solo shot to right in the sixth. Holliday and Hawpe are tied for the team lead with 15 homers.
Pirates pitcher Ian Snell (3-8) took solace in the fact he kept the damage to a minimum, only giving up four runs -- three earned -- on six hits in six innings.
"They're a good hitting team," Snell said. "If I held them to three runs, four runs, I can hold any team to three, four runs."
Willy Taveras scored the Rockies' third run in the second inning when he walked and stole his Major League-leading 40th and 41st bases on consecutive pitches. He came around to score when Ryan Doumit's throw to third sailed into left field.
"We knew our offense would come around," Colorado catcher Chris Iannetta said. "We just needed to get it in tune with our pitching."
On Friday, both sang in perfect harmony.
Jeff Birnbaum is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.