Luis Mendoza was a broken pitcher when the Royals took him off the Rangers’ hands in a 2010 trade. It wasn’t that Mendoza, who won the fifth spot in Royals’ rotation during spring training and will make his second start in Friday’s series opener against Toronto, lacked big-league stuff. Mendoza, 29, lacked confidence. He’d had some success in the minors, particularly during the 2007 season with the Rangers’ Class AAA affiliate. Mendoza went 15-4 with a 3.93 ERA in 26 appearances that season for the Frisco (Texas) RoughRiders. But Mendoza struggled to duplicate that success at the big-league level, going 4-8 with a 7.73 ERA during three brief stints from 2007-09 with the Rangers. When he arrived in Kansas City, the Royals put him in the bullpen, but he promptly coughed up 10 runs in four innings and was demoted to Class AAA Omaha by mid-April. “I wondered if I’d ever be back in the big leagues again,” Mendoza said. “I felt healthy, my velocity was good and I knew I had good pitches. It was a matter of figuring out what I was doing wrong. There’s a lot of questions in your mind when you’re struggling.” Enter Doug Henry, an 11-year big-league veteran with five teams — including his last year in 2001 with the Royals. Henry was in his first season as Omaha’s pitching coach when Mendoza arrived, and it’s Henry who finally got through to Mendoza — tweaking his delivery and cultivating trust in his sinker. “When we first signed him, he had a few rough outings up here and apparently had some rough outings before we got him,” said Henry, who is in his first season as bullpen coach for the Royals after three seasons at Omaha. “I told him what I saw. He started to make adjustments and had a couple good outings, but he didn’t feel comfortable and went back to his old ways. “He had a couple more bad outings, but then he finally came to me and said, ‘I’m ready.’ It was a mind-set on his part. Once he made that commitment, he became extremely coachable and made those adjustments. When he changed, he just took off.”