Aaron Boone benches struggling Didi Gregorius

KANSAS CITY, Mo. — The combination of Didi Gregorius being in a 1-for-45 slump and the Royals starting lefty Danny Duffy got the shortstop a seat on the bench at the start of Saturday night’s game. “It’s a combo. It’s good for him to get a little break and matchup wise this is the one…