After carrying just 11 position players for the first two games of an Interleague series with the Astros at Minute Maid Park, the Royals took 12 into Wednesday's rubber game.
Manager Ned Yost said Falu's versatility made him the most attractive option.
"Falu can play everywhere on the field, has played everywhere on the field," Yost said. "He's a switch-hitter off the bench."
Kansas City considered bringing up Johnny Giavotella, the Royals' second-round Draft pick in 2008 who was optioned to Omaha on June 12, but Yost didn't want to bring him up just to sit on the bench.
"We brought Falu up, who can play multiple positions, can swing the bat effectively from both sides of the plate," Yost said. "He makes a great utility guy."
Falu, 29, is batting .326/.326/.442 in 43 at-bats for the Royals this season. He last played on May 30. Falu saw action at second base, shortstop and third base during his previous stay with the Royals. He has also played some right field for Omaha this season.
At Omaha, Falu batted .333/.397/.516 in 126 at-bats. In his last 10 games, he batted .351 with three homers and 12 RBIs.
Falu said he was extremely happy to be back in the Royals' clubhouse after working hard in Omaha.
"That's why when I was sent down, I was thinking that my goal is to go back to the Majors," Falu said. "I played very well there."
Coleman, called up to provide some needed bullpen depth, has a 4.91 ERA in 22 innings for the Royals this season. He pitched in Monday's 9-7 loss to the Astros, giving up five earned runs in two innings.
Clark Goble is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.