The good news here for Indians fans is McDonald is a very good defensive player. He can play second base, shortstop or third base to an above average level, even at age 38. The bad news is that he's a poor hitter. He's a career .237/.275/.328 line, good for a putrid 60 OPS-plus.
Through only 35 plate appearances with the Pirates this season, McDonald hit .065/.171/.097. He did hit .249/.295/.386 with nine doubles and six homers in 70 games last season for the D-Backs, though, so that kind of production as a backup could be enough to stomach, given his good defense.
As far as the Pirates' return, don't expect much. Players named later are rarely of consequence and any cash moved for McDonald is sure to be minimal.
McDonald has been on the disabled list since May 14 but was on a minor-league rehab assignment when news of the trade broke. He'll provide depth with shortstop Asdrubal Cabrera on the disabled list.