Buckner, now with the parent club, was 9-7 with a 3.78 ERA in 27 games (15 starts) for Omaha. He had 83 strikeouts and just 26 walks in 104 2/3 innings.
Aviles, who played second and third base as well as shortstop, has a .298 average with 15 home runs and 74 RBIs. He leads the club with 152 hits, 75 runs and six triples.
Other players and pitchers of the year in the Minor League system:
Wichita (AA) -- Mike Stodolka is batting .291 and tops the Wranglers with 12 homers, 59 RBIs and 73 walks. A former pitcher, he's in his second season as a first baseman.
Left-hander Dusty Hughes is 5-2 with a 3.54 ERA in 23 games (14 starts). He also was the top pitcher for the Arizona Royals in 2003.
Wilmington (A) -- Left-hander Rowdy Hardy has a 15-4 record and a 2.43 ERA in 25 games (21 starts) and leads the Carolina League in victories.
Outfielder Jose Duarte, a speedy right-handed hitter, is batting .287 with 24 doubles, 79 runs and 33 stolen bases in 42 tries.
Burlington, Iowa (A) -- Outfielder Joe Dickerson leads all regulars with a .289 average and 121 hits. He has 26 stolen bases.
Right-hander Mario Santiago is 5-10 with a 3.77 ERA in 25 games (19 starts) for the Bees. He's held opponents to a .249 average.
Idaho Falls (Rookie) -- First baseman Clint Robinson leads the Pioneer League with 59 RBIs and has 14 homers and a .338 average. Right-handed closer Greg Holland has a 6-1 record, four saves and a 3.30 ERA in 19 appearances.
Burlington, N.C. (Rookie) -- Outfielder Wilson Tucker had a .298 average, eight homers and 41 RBIs, earning a promotion to Idaho Falls. Undrafted pitcher Anthony Bradley had a team-best 2.90 ERA, a 2-2 record and three saves while starting and relieving.
Arizona (Rookie) -- Right-hander Matt Mitchell is 5-1 with a 1.94 ERA in 13 games (six starts) with 65 strikeouts in 51 innings. First baseman David Wood leads the club with a .324 average and 39 RBIs with a league-high 68 hits.
Dominican (Rookie) -- Shortstop Angel Franco, a switch-hitter, leads the club at .282 and 14 stolen bases. Right-hander Giancarlos De La Cruz has a 3-2 record and a 1.13 ERA in 12 starts. Both are 17 years old.
Gathright has infection: Outfielder Joey Gathright, despite his .378 average this month, was out of the lineup on Tuesday night because of an eye infection.
"It's nothing serious. I woke up Monday with an irritation in my right eye so I'll miss today's game," Gathright said. "I went to see the doc and I got a lot of eye drops. It feels like there's an eyelash in there."
Gathright was wearing glasses because the irritation prevented his wearing contact lenses as he usually does. If necessary he can wear the glasses in a game, as he has done in the past. He was wearing his specs when, in the sixth inning, he replaced Esteban German in left field.
Rotation revision: The Royals decided to flip-flop two of their starters, going with Leo Nunez on Thursday against the Tigers and Kyle Davies on Friday in the first game of a doubleheader at Minnesota.
Nunez has not pitched since Aug. 21 and this gives Davies an extra day of rest from his last start on Saturday night.
Manager Buddy Bell still hasn't decided on Saturday's pitcher against the Twins except that it won't be Jorge De La Rosa. He had a rough rehab outing on Monday night at Wichita and will have another Minor League start.
That leaves the choice between Brandon Duckworth and Buckner. Buckner had five impressive innings in his debut against the Indians and Duckworth worked seven shutout innings Sunday at Omaha.
"I don't know how that happened, especially at that ballpark with the wind blowing out," Duckworth said.
Duckworth last pitched for the Royals on June 13 when he suffered a rib-cage injury. He's been satisfied with his progress recently.
"I just needed to get command of the breaking ball. And once I did that, I felt good and I was able to get ahead and stay ahead and not go into too deep counts," he said.
"Everything felt really good. The ball came out of my hand really well. And I had good command of everything and I got ahead and stayed ahead. That's the biggest accomplishment of it all."
In Buck's seat: Chaplain Floyd Sullivan of Leavenworth, Kan., was Tuesday night's occupant of the Buck O'Neil Legacy Seat. He is chaplain at Eisenhower Veterans Hospital and pastor of Mount Olivet Baptist Church in Kansas City. A Vietnam veteran, he has helped thousands of soldiers in 23 years as an Army chaplain.
Royals rundown: Craig Brazell hit his Minor League-leading 39th home run, but Omaha lost to Nashville, 11-4, on Monday. Justin Huber banged his 16th homer. ... The Wichita Wranglers bowed out of Lawrence-Dumont Stadium with a 10-1 loss to Tulsa. The Double-A club, affiliated with the Royals since 1995, next season will become the Northwest Arkansas Naturals. ... Wilmington's magic number is two for the second-half title in the Carolina League North after a 6-3 win over Lynchburg. It was the sixth straight win for the Blue Rocks who have their last seven games at home. ... Brady Everett had his 10th homer for Burlington, Iowa, in a 6-4 loss to Wisconsin. ... Top Draft pick Mike Moustakas did not play for the second day for Idaho Falls, an 8-1 winner over Orem. He hasn't played since going 2-for-5 in his pro debut on Saturday. ... Kyle Martin hit his team-high 10th homer as Burlington, N.C., closed its season with a 6-4 loss to Bristol and a 38-30 record. ... Wood hit two homers in the Arizona Royals' 8-2 loss to the Angels. He has five this season.
Coming up: The Royals meet Detroit in the second of three games at 7:10 p.m. CT on Wednesday at Kauffman Stadium. The Tigers will start rookie left-hander Andrew Miller (5-4, 4.97 ERA) against Zack Greinke (5-5, 4.25).
College students can get a $14 ticket for $5 by showing their student identification at the stadium. Ticket windows open 90 minutes before game time.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.