The club also announced that right-hander Neftali Feliz was reinstated from paternity leave -- he had a daughter named Nashly. Right-hander Miguel Almonte was optioned back to Omaha.
In two stints with the Royals this season, Soler is hitting .154 with two home runs and six RBIs. Soler, acquired in the offseason in a trade for closer Wade Davis, had been splitting time at DH with Brandon Moss, who also is struggling.
Royals manager Ned Yost said there was no value in keeping Soler on the Major League club where he wasn't getting consistent playing time.
"Just been a struggle for him to get going," Yost said. "He doesn't look comfortable in the box. Hasn't been able to get on a roll.
"We just need him to keep getting at-bats, continue to develop."
Yost continues to view Soler, 25, as a potential "Sano-type," referring to Twins third baseman Miguel Sano, who hit .239 last season in 495 plate appearances. But Sano, now in his third season, entered Monday's action hitting .270 with an .892 OPS to go with 21 home runs.
"[Soler] has got that kind of power, too," Yost said. "He just needs to play and develop."
The Royals, who started the day two games out of first place in the American League Central, simply couldn't afford to keep waiting on Soler.
Yost also is hoping that with more consistent at-bats, Moss will rediscover his power stroke. Entering Monday's series opener against the Tigers, Moss had hit one home run since May 27 and was hitting .191 overall.
"[Moss is] intriguing because if he gets hot, he can carry you," Yost said. "He can hit a bunch of home runs. Hopefully, we can get him in a position to where he can get hot by playing more."
Burns will be used primarily as a late-inning pinch-runner, while also spelling Lorenzo Cain in center field. Burns is hitting .259 at Omaha with 14 stolen bases.