Dropped off the Spring Training roster were pitchers Brandon Duckworth, Roman Colon and Tim Hamulack.
The leaves the Royals one above the limit which must be reached by 2 p.m. CT on Sunday. The Royals open the season at 1:05 p.m. on Monday at Chicago.
The final roster spot comes down to a decision between catcher/utility man Brayan Pena and outfielder Shane Costa.
Pena, a Cuban defector who recently gained U.S. citizenship, was an unlikely candidate to make the roster because few teams carry more than two catchers.
But Pena offers versatility.
He's not only a catcher but also capable of playing third base or the outfield, both positions where he played during Spring Training. He has also played first base.
On top of that, he's a switch-hitter who could come off the bench to pinch hit. Last season at Omaha, Pena batted .303 with six home runs and 31 RBIs in 60 games. In Arizona games this spring, he batted .275 with one homer and four RBIs.
By having a third catcher, Hillman might feel freer to manipulate his two catchers, Miguel Olivo and John Buck, without feeling compelled to keep one on the bench in event of an injury at that demanding position. He could even use one as designated hitter while the other catches if he wanted.
Pena, 27, also is out of options, and with good catchers in thin supply, the Royals anticipate he'd be claimed if they tried to get him through waivers.
His previous Major League experience consists of 71 games, an aggregate of brief stays with the Braves in each of the past four seasons. His big league average is .228 (29-for-127) with two homers and 12 RBIs.
Costa, coming back off surgery on his right wrist, has spent his entire seven-year career with the Royals. His average was .295 for Omaha last season with 10 homers and 42 RBIs in 75 games when surgery stopped him.
He had a very successful Spring Training with a .455 (15-for-33) average, although he was used sparingly.
In parts of the three previous seasons with the Royals, Costa played a total of 154 games with a .254 average. He is also out of options.
Maier had a good spring as he batted .297 (19-for-64) and knocked in 17 runs, second most on the club, with three homers. But he had options remaining.
Last year, after hitting .316 in 85 games for Omaha, Maier was called up by the Royals. On Aug. 20, he was struck in the face by a pitch at Cleveland, and despite frightful bruising and a cheekbone fracture, he missed just 19 games. In 34 games for Kansas City, he batted .286.
Hillman had indicated on Friday that the official moves were coming on Duckworth, Colon and Hamulack. All three were on Minor League contracts.
In nine Cactus League games, Duckworth had a 4.67 ERA, and he's likely to be in Omaha's rotation. Colon, a reliever, appeared in 11 spring games with a 4.50 ERA. Hamulack, a left-handed reliever, posted a 2.57 ERA in nine outings.
The Royals' Opening Day roster for Monday at Chicago will not include starting pitcher Sidney Ponson, who won't be activated until before he pitches the home opener on Friday at Kansas City. When he's added, a player will have to be dropped.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.