Danny Duffy (elbow) allowed six runs on seven hits and two walks over just 2 1/3 innings in his first rehab start for Triple-A Omaha on Monday. Duffy posted a 4.22 ERA and struck out 15 over 10 2/3 innings in his first three rehab starts, but he was obviously off in this one. The left-hander is on track to return in late June but will need to improve his results before the Royals add him to the big league rotation.