Pirates placed INF John McDonald on the 15-day disabled list with lower back discomfort. McDonald suffered the injury during Tuesday's game and will now get some extended rest. The 38-year-old has just two hits in 31 at-bats this season. Jordy Mercer has returned from Triple-A Indianapolis to replace him on the active roster.

John McDonald left Tuesday's game against the Brewers with lower back discomfort. The ailment figures to sideline McDonald for at least a few days. He has just two hits in 31 at-bats for the Pirates.

Pirates acquired INF John McDonald from the Diamondbacks for a player to be named later. FOX Sports' Ken Rosenthal first reported the deal while CBS Sports' Jon Heyman passed along word about the player to be named later. McDonald, 38, batted .249/.295/.386 with six home runs in 213 plate appearances last season while making appearances at shortstop, second base and the hot corner. Known as a solid defender, he should be a useful bench player for Pittsburgh.

FOX Sports' Ken Rosenthal reports that the Pirates have acquired infielder John McDonald from the Diamondbacks.

FOX Sports' Ken Rosenthal reports that the Diamondbacks are looking to trade infielder John McDonald. McDonald is expendable because of the presence of Cliff Pennington and Willie Bloomquist. The 38-year-old isn't much of a hitter, but he is a solid defender capable of playing multiple positions. He's due to make $1.5 million in 2013.

John McDonald homered and singled in a run against the Dodgers on Sunday. The Jake Elmore experiment hasn't gone too well, so the Diamondbacks have turned back to McDonald at shortstop the last two days. It might be a short-lived thing, though; now that they're pretty much completely out of the race, it won't hurt to give Elmore more reps.

Diamondbacks activated INF John McDonald from the 15-day disabled list. McDonald will be back in his D'Backs uniform for Tuesday night's game against the Rockies. The veteran infielder missed about a month with a strained oblique.

John McDonald (oblique) began a rehab assignment Thursday with the Diamondbacks' rookie-level Arizona League team. McDonald has been out since early July with a strained oblique and his recovery was slowed by a case of bronchitis over the All-Star break. He could be activated sometime this weekend.

John McDonald (oblique) could be activated from the disabled list by the end of the week. McDonald took some swings in batting practice Sunday with no issues. "He's back at our spring facility, and he's getting better," Diamondbacks manager Kirk Gibson said. "He's starting to kind of let it go and that's what he was waiting for." McDonald has been out since early July with a strained oblique.

Diamondbacks placed INF John McDonald on the 15-day disabled list, retroactive to June 25, with back tightness. Assuming the injury isn't serious, McDonald could return when the Diamondbacks begin the second half of the season. Geoff Blum was activated from the 60-day disabled list to replace him on the active roster.