In 1990, Jefferies raised his batting average to .283 while scoring 96 runs and leading the NL with 40 doubles, but the Mets finished 2nd for the second straight year. He slipped in 1991, hitting .272 with 30 extra base hits in 486 at bats as the team slipped to 5th place. That off-season the team traded him, along with McReynolds and infielder Keith Miller, to the Kansas City Royals for former All-Star pitcher Bret Saberhagen and utility man Bill Pecota, ending his stay with the Mets.