KANSAS CITY, Mo. -- With several significant Kansas City Royals about to hit the free agent market, they will need young players to come through for them next year.

Two did on Saturday night.

Jake Junis logged his ninth victory and Jorge Bonifacio blasted a three-run homer as the rookies rallied the Royals to a 4-3 victory over the Arizona Diamondbacks.

"We're expecting to win with them next year," Royals manager Ned Yost said. "It was nice to see 'Boni' produce right there with the big blow. (Rookie Ramon) Torres with the big hit to keep the inning going. It gave Junis the opportunity to win the ball game."

Junis (9-3) shares the American League lead for rookie pitchers. He limited the Diamondbacks to two runs and five hits in six innings.

One of the hits was a home run by A.J. Pollock in the sixth.

"My sinker saved me," Junis said. "I struggled with my command a little bit. I got some outs with my sinker. The defense played great behind me and saved my butt a few times."

Bonifacio's sixth-inning home run was his 17th of the season, the most by a Royals rookie since Eric Hosmer hit 19 in 2011. Hosmer homered on a 2-2 offering off Archie Bradley (3-3).

"You don't ever want to second-guess yourself," Bradley said. "I made the pitch and he hit it. It was kind of right down the middle 2-2, I didn't want to go 3-2. I wasn't feeling great with my command, so I wanted to not necessarily challenge him, but throw a sinker down and in, and then just threw it right down the middle and he hit it."

Daniel Descalso's triple in the eighth scored Pollock, trimming the Kansas City lead to one run.

Mike Minor picked up his sixth save but had to work around a Christian Walker pinch-hit double to lead off the inning.

David Peralta doubled on Junis' first pitch. Ketel Marte drove Junis' second pitch to deep center, but Lorenzo Cain made a web-gem catch to rob him of extra-bases and an RBI.

"That was a big one in the first inning when Cain ran that one down by Marte and banged up against the wall," Junis said. "That definitely saved a run there."

The Royals scored first in the fourth inning, which Cain led off with a walk. Hosmer singled and Cain swiped third for his 26th stolen base and scored when Mike Moustakas grounded into a double play.

The Diamondbacks tied it in the fifth. Rey Fuentes walked and stole second. Peralta's double down the first-base line scored Fuentes.

Alcides Escobar doubled with one out in the fifth, his 16th extra-base hit in September to set a Royals' record for a calendar month by a shortstop. Escobar was stranded.

Arizona starter Taijuan Walker was pulled after five innings and 76 pitches. He allowed one run and three hits, walked one and struck out six. Bradley replaced him.

"I thought his stuff was really good. An aggressive fastball, a really good breaking ball, some changeups. I thought it was a really, really effective outing. He walked off the mound after five innings with a chance to win the game. It's just unfortunate that we didn't get the opportunity for him."

Walker was pleased with his performance.

"It was good. It's solid," Walker said. "It was good to finish the regular season on a high note and get ready for the playoffs.

NOTES: Diamondbacks manager Torey Lovullo made it official when he said RHP Zack Greinke will start the wild-card game Wednesday against the Rockies. ... Arizona C Jeff Mathis, who was on the disabled list with a broken right hand, was activated and started. ... Diamondbacks RHP Jimmie Sherfy is day-to-day with right triceps tightness. ... Royals LHP Danny Duffy will undergo a minor procedure Tuesday to remove floating chips in his elbow, which created inflammation this season. ... Royals 3B Mike Moustakas was honored before the game for breaking the club season home run record with 37. He and his father, who is also named Mike, threw out the ceremonial first pitch. ... LHPs Robbie Ray of the Diamondbacks and Jason Vargas of the Royals are the starters for the season finale. Vargas will be going for his 19th victory, which would lead the American League.