The presence of a left-handed bat proved decisive Friday when the Royals selected George Kottaras over Brett Hayes as the backup to starting catcher Salvy Perez. “It was a coin flip,” manager Ned Yost said. “They both did a nice job behind the plate. Both guys swung the bat really well. It was just the advantage of having an extra left-handed bat on the bench if we need it.” Kottaras has a .220 career average in 249 games over parts of five seasons with Boston, Milwaukee and Oakland. But he also has 24 homers and 84 RBIs in 592 career at-bats. “It’s one of those things,” Kottaras said. “They had to make a choice. All I did this spring was try to focus on myself, try to get better and work on some things here and there. It worked out.” The Royals said Hayes, a right-handed hitter, cleared waivers and accepted an outright assignment to Class AAA Omaha. He had the option of choosing free agency because because of his service time in the big leagues. “The days that Salvy does need days off,” Yost said, “will probably be against tough right-handers. That’s when you’ll want to give him a break. That’s where the left-handed bat comes into play.” Keeping Kottaras effectively completes the Royals’ 25-man roster for Monday’s season opener against the White Sox in Chicago, although veteran infielder Miguel Tejada must still be added. “He’s made our club,” Yost confirmed. “He and Elliot Johnson will be our two utility guys. So we are settled and set.” All clubs have until 2 p.m. Central time Sunday to make their decisions official. The Royals are also likely to place left-hander Danny Duffy on the 15-day disabled list as he continues his recovery from Tommy John surgery.