"As a baseball player myself, to say I took part in the same dugout as George, is something I know my dad's jealous of," first baseman Eric Hosmer said. "We all enjoyed the time he spent with us. We were hoping he'd stick around, but George has got stuff he needs to do."
Pedro Grifol, who was previously a special assignments coach, is the now the club's hitting coach.
Brett and Grifol were hired on May 30 when the Royals were 21-29. Since then, they've gone 26-22 and a pair of sluggers have heated up.
Mike Moustakas was batting just .187 (28-for-150) in the first two months, but during Brett's time, the third baseman hit .266 (38-for-143). Hosmer was batting .262 (45-for-172) with nine extra-base hits and one home run before May 30 and shot up to .309 (60-for-194) with 22 extra-base hits and 10 home runs during Brett and Grifol's tenure.
While Grifol handled most of the technical work like going over video and designing personalized drills, Hosmer said Brett's biggest influence came in plate approach and attitude.
"When George gets in there, he's so competitive and all he wants to do is win," Hosmer said. "When you're around a guy like George and he's acting like that in the dugout it gets you fired up."
Brett said he plans to continue throwing batting practice before home games, but will sit in an upstairs suite with general manager Dayton Moore after first pitch.
"He's expressed to us all that he's a phone call away and if we ever need anything, can always count on him," Hosmer said. "It's pretty cool having someone in your corner like that."
Kathleen Gier is an associate reporter for MLB.com.