That's really all the information we have right now, so we don't know what the Diamondbacks got back in exchange, assuming that the report turns out to be correct. It probably won't be all that much, considering McDonald's age and offensive production, but I'll be kinda sorry to see him go. His glove-work was almost impeccable, and it was a pleasure to watch him vacuum up balls on the left-hand side of the infield.
In two years with Arizona, McDonald appeared in 89 games, with a triple-slash line of .230/.278/.344. That's a .622 OPS, which is only an OPS+ of 61. Normally, thawould be well below replacement level, but such was the quality of McDonald's defense, that he posted 1.1 bWAR or 1.5 bWAR for the Diamondbacks, since coming from the Toronto Blue Jays in the Aaron Hill for Kelly Johnson in August 2011. Frankly, I'd probably rather have seen Willie Bloomquist traded for that reason - he's a slightly better hitter, but has much worse defense. However, the roster crunch likely made this trade inevitable.
As we noted this morning, the team was looking to help McDonald out, by trading him to a team where he'd see playing time, and near his home in Connecticut. The Pirates particularly need help for their infield, Chase D'Arnaud being out with a thumb ligament issue which required an operation yesterday. We'll update this story with more information on the return, when we get it. [H/T rfffr]
Update. The deal is now confirmed from multiple sources, and the D-backs will be getting back a player to be named later, or cash. The former might suggest a prospect selected in the 2012 draft by Pittsburgh, not yet eligible to be traded, but we won't know if that's the case until it happens. Oddly, it's the second time McDonald has been dealt for a PTBNL, as he was sent to the Blue Jays from the Indians in December 2004 for one [it turned out to be Tom Mastny]