Jordy Mercer had only a few hours to unpack his bags before the Pirates beckoned him back to the majors. This time, he hopes he can settle in for a little bit longer. Two days after optioning Mercer to the minors, the Pirates recalled the infielder Wednesday and placed backup shortstop John McDonald on the 15-day disabled list with a lower-back injury. Tuesday, one day after the Pirates optioned him to Class AAA Indianapolis, Mercer drove from Pittsburgh to Indianapolis. Five hours after unpacking his bags, he was told to pack them again. This time, he got to fly. McDonald left the Pirates' 4-3 victory Tuesday night after tweaking his back in a one-swing at-bat in the 11th inning. Officially a lower-back strain, it is possible McDonald might have played his final game as a Pirates player. He is hitting .065 with a .171 on-base percentage. "Johnny Mac's issues came up all of a sudden," manager Clint Hurdle said. "You watch a guy take that swing of a bat and hit the ball, and then two minutes later, the trainer's pulling on my shoulder and saying he can't play." The Pirates acquired him in a trade with the Arizona Diamondbacks in March to add shortstop depth after Chase d'Arnaud had thumb surgery for a torn ligament in his left hand. D'Arnaud is eligible to come off the disabled list June 1. Mercer hit .258 in nine games with the Pirates entering Wednesday and hit .333 in 26 games with Indianapolis.