DENVER -- If Johnny Cueto made his final start for the Cincinnati Reds on Saturday night, it was dazzling.

The Reds ace stifled the Colorado Rockies, limiting them to four singles in eight scoreless innings in Cincinnati's 5-2 win.

Third baseman Todd Frazier backed Cueto with a three-run homer as the Reds opened a 4-0 lead in the third inning.

With the Reds languishing in the standings and with Cueto eligible to be a free agent after the season, he is a prime candidate to be traded before Friday's non-waiver deadline.

Before Cueto took the mound against the Rockies, there was some question as to whether he would pitch. Michael Lorenzen, the Reds' scheduled starter on Sunday, was throwing in left field 25 minutes before the game. And as Cueto warmed up in the bullpen, Lorenzen appeared.

"I said, 'What are you doing here?'" Cueto said through a translator. "He said I'm going to pitch because you're going to get traded.' That happened 10 minutes before the game."

When Cueto finished his stellar outing, he was hugged by nearly every one of his teammates -- firm embraces and perhaps farewells.

"Every time I come to the ballpark, I feel like this is the last time," Cueto said. "My teammates are feeling the same way. Something is going to happen. They're going to trade me, so I don't know what's going on."

In his previous two starts, Cueto allowed a combined seven runs (five earned) and 11 hits in nine innings. But Cueto (7-6) was his vintage self against the Rockies. He did not allow a runner to reach second base, issued his lone walk in the eighth and struck out five while throwing 100 pitches.

"I'm telling you, man, today he was on a mission," Reds catcher Brayan Pena said. "I saw something in his eyes that I never saw before. He was ready today.

"He knew that he needed to step it up because the last couple starts they weren't too good for him. He said, 'Pena, today you're going to see something different. I'm going to be me.' And that's exactly what he did. When he's on, he's a game-changer."

Cueto threw a first-pitch strike to 21 of the 28 batters he faced, varying his delivery and creating a huge challenge for the Rockies.

"He's one of those guys that you won't feel very comfortable at the plate," Rockies right fielder Carlos Gonzalez said, "because if you try to do too much, he's really smart and he will get you out quick."

Rockies starter Chris Rusin (3-4) had pitched at least six innings in his five previous starts but lasted five innings against the Reds, allowing 10 hits -- nine singles and Frazier's homer -- one shy of his season and career high set June 11 at Miami.

The Rockies scored two runs in the ninth against reliever Jumbo Diaz. Gonzalez singled home the first run and the second scored when Reds shortstop Eugenio Suarez booted left fielder Corey Dickerson's two-out grounder.

Reds closer Aroldis Chapman came on and posted his 20th save of the season by getting pinch-hitter Michael McKenry to ground out. It was Chapman's third career one-out save.

Reds center fielder Billy Hamilton tied his career high with three hits, scored twice and stole his major league-leading 46th base of the season.

An overturned call involving Hamilton led to an unearned run in the fourth and a 5-0 Reds lead.

Hamilton led off the inning with a single. He broke for second and appeared to be picked off, but Rockies first baseman Ben Paulsen threw the ball into left field.

With one out, Hamilton broke for home on a grounder to shortstop Troy Tulowitzki. Paulsen fired the ball to the plate. Hamilton, sliding headfirst, was called out. But Reds manager Bryan Price challenged and the call was reversed.

The Reds used seven hits in the third inning to open a 4-0 lead while batting around and making Rusin throw 34 pitches.

Hamilton led off with a bunt single. Second baseman Brandon Phillips and first baseman Joey Votto followed with singles that produced a run. Frazier then belted a three-run homer -- a liner to right that just cleared the out-of-town scoreboard for his 27th home run of the year and No. 100 in his career.

That was more than enough for Cueto, who brushed aside the surprising news from Lorenzen about a possible trade and zeroed in on his start -- maybe his last one -- with the Reds.

"That was really bad how I found out what happened," Cueto said. "My thoughts were all over the place. When they say that, it was something really bad to me at that moment."

NOTES: Rockies RHP Christian Bergman (right shoulder inflammation) threw 35 pitches in a simulated game and felt fine. Assuming he is OK when he reports Sunday, Bergman is scheduled to start Tuesday for Triple-A Albuquerque against Salt Lake and throw three innings or 45 pitches. ... Rockies RHP Brooks Brown (right shoulder inflammation) will throw 25 pitches to hitters on Monday at Albuquerque. ... Reds 1B Joey Votto entered Saturday leading the majors since the All-Star break in hitting (.548), on-base percentage (.641) and hits (17) while ranking second in slugging percentage (.903). ... Rockies 2B DJ LeMahieu's single in the ninth inning gave him a career-high 15-game hitting streak. ... Rockies 3B Nolan Arenado was hit on the left hand with a pitch from Reds RHP Johnny Cueto in the seventh inning and stayed in the game but was lifted for a pinch hitter in the ninth. X-rays were negative, and Arenado was listed day-to-day with a hand contusion.