Hillman said that would not necessarily be restricted to Interleague games at National League parks when no DH is used.
The decision clears the way for Ross Gload and Ryan Shealy at first base.
"I like the lateral range of a Shealy and a Gload better than I like the lateral range of Billy Butler. But I like Billy's footwork around the bag and his hands defensively overall have been pretty good," Hillman said.
Gload, a left-handed batter, has a two-year contract and is presumed to be a roster lock and the starting first baseman on Opening Day against Tigers right-hander Justin Verlander.
Shealy has options remaining and could be sent to the Minor Leagues, but Hillman has been impressed by him.
"I've seen him on any given day center up both fastball and secondary pitches. He got put behind a little with the sickness [flu], but he caught fire right when he got back and hit a couple of home runs," Hillman said.
"He plays a good defensive first base. He had a couple of real nice plays coming off the bag the other night with tags on throws from Alex [Gordon]. I like his lateral range and I like his movement. We'll have to see how the roster shakes out."
The Royals face a roster pinch because, pending catcher Miguel Olivo's appeal of a five-game suspension, they will start the season a man short with 24 players on the roster. Even with 25, the roster makeup depends on whether 11 or 12 pitchers are kept.
The 21-year-old Butler signed as a third baseman, but was switched to the outfield in the Minors. Last season, he played 22 games at first base for Triple-A Omaha and 13 more for the Royals, mostly in September.
Butler's ambition is to be more than a DH.
"I'm not satisfied doing that. It's one of those things. That's my role right now," Butler said. "Like [Hillman] told me, he's not going to be afraid to put me in there whenever it fits in. He told me he's real pleased with the way I've come along. We've just got other guys over there that need time, too."