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.

About four hours before first pitch Wednesday, backup catcher Michael McKenry was working out at second base, firing throws toward first base.

But don't look for McKenry to start spelling Neil Walker in the infield.

After an atrocious night controlling the running game Monday -- the Brewers went 6 for 6 in steal attempts -- McKenry worked at second in a throwing drill the Pirates hope will help him behind the plate.

It is similar to the way some athletes cross-train in other sports to improve muscles and mechanics that often aren't addressed in their normal routine.

"Sometimes, you get them out of that mentality of being behind the plate, doing drills there," Hurdle said.

"You put them in another environment, another atmosphere with the same mechanics involved. Hopefully, it can free him up and tighten him up and sharpen him up."

Former Pirates pitcher Jonathan Sanchez will sign a minor league contract with the Los Angeles Dodgers, according to an ESPN.com report Wednesday.

Sanchez, 30, was released by the Pirates last week after the left-handed pitcher cleared waivers. The team designated Sanchez for assignment April 30 after he went 0-3 with an 11.85 ERA in five appearances, four starts, with the Pirates.

After signing a minor league contract with the Pirates in the offseason, Sanchez won a spot in the starting rotation with a couple strong outings late in spring training.

The Pirates might juggle their starting rotation after an off day Mon day.

The Pirates' three left-handed starters are pitching consecutive games, and Hurdle said they could alter that schedule to give opposing batters different looks.