In 2008 there was Ray Durham. In 2011 there was Jerry Hairston, Jr. And in 2014 there is Gerardo Parra.
Mitch Haniger's best-case, and I mean best case, scenario as a major league player is basically what Gerardo Parra has been over the past few years. Haniger has not shown a whole lot in the minors with his bat as of yet, but has stuck around the prospect lists with defensive versatility in the outfield. What's the best case scenario for Haniger? It probably looks something like him managing center field or playing excellent defense on the corners and sneaking in an average-ish batting line as a major league player. Interestingly, that's a pretty good summary of Parra's MLB career so far. Put more simply, the talk about Mitch Haniger coming up through the minors reminds me a lot of the talk about Logan Schafer coming up through the minors, and I think the Logan Schafer career track is more likely for Haniger than the Parra career track. Haniger is an asset, but the Brewers did not have to give up much value to make this deal.
Parra has been an intriguing player but is having a very down year so far. In 2011 and 2012, he was roughly an average player overall manning the outfield for the Diamondbacks, which is in no way a knock on his abilities-- average players have plenty of value in this game. He accomplished this by playing above-average defense but also hitting about as well as the league average. That was in part due to him being shielded somewhat from left-handed pitchers. In 2013, UZR really, really, really liked his defense, and as a result he basically graded out as an all-star caliber player if you believe that his defense was 26 runs better than an average corner outfielder. This year he has struggled in all areas. UZR doesn't even like his defense so far, but in the same way a great batter can have a bad stretch of 100 at-bats, a great defender can have a bad stretch of half a season.
The short version of the story is that if you were to go about projecting Gerardo Parra for next season, he's at worst a passable platoon option for an outfield spot and at best an above-average, near-everyday player. The role he is being asked to fill in for the Brewers is to back up all 3 spots, play left field occasionally against tough righties, and probably replace Khris Davis defensively in the late innings. He fits that role really well and did not cost very much to acquire. Even if Parra is non-tendered after this season, that makes this trade probably about even value. If his bat comes back around, he's a viable option for the heavy end of an outfield platoon and a potential asset to play with in the offseason.
If there was disappointment about this trade in the Brewer blogosphere, I think it had much more to do with what might have been. There were essentially 3 ideal types of trade pickups for the Brewers-- a lefty outfielder with a passable bat, a power-hitting lefty corner infielder, and a right-handed reliever. Melvin got the ideal player for target number one. But the Diamonbacks also had an ideal player for target number 3, in Brad Ziegler. He's a righty with a weird, sidearming delivery that makes him extra effective against right-handers-- or so you would think, as he actually has a reverse platoon split on the year. Regardless, he is a good pitcher who would have fit very nicely into the back end of the Brewer bullpen to pair with Smith and Duke in the setup mix right now, and could have been a nice guy to bring on to get a tough right-hander later in the year in certain situations if Jim Henderson and Tyler Thornburg are able to return from injuries and be effective. Had another mid-level prospect brought back Ziegler along with Parra, I think yesterday would have gone from "modest win" to "big win".
Though it does not drastically change any projections for the rest of the season (and for the record, I don't think any moves made in the Central really do), Doug Melvin pulled off a solid trade that provided a valuable role player to 2014 squad, important depth in case of a major injury, and some potential value in 2015. On those grounds, the trade was a success. But there still may be work to be done in August.