This move makes a fair amount of sense in terms of the current construction of the team, because Willingham is a righty and the Pirates’ lineup against lefty pitching is awful, and because lefties are the only real weakness in the Pirates’ bullpen. Willingham is a poor defender who wouldn’t be a great defensive fit for PNC Park, but other than that, I can see why the Pirates would want to do something like this.
Whether this move makes sense in the long term depends on how valuable the Pirates consider Jones to be. He’s under control for many more years, while Willingham isn’t, but if the Pirates think that Jones isn’t going to be a long-term fixture in the outfield (and I don’t think he is), then they can make a trade like this and not worry about it. Willingham should bring back a draft pick or two when he hits free agency, as well.
For more on the Pirates, check out Bucs Dugout.