Gerardo Parra began his season in Arizona but he'd end it in Milwaukee. Rewind the clock to July 31st. The Brewers sat atop the NL Central two games ahead of the second place Cardinals. It seemed like nothing short of a historic collapse *cough* would stop the Brewers from reaching the postseason.
Still, many wanted the Brewers to trade Jimmy Nelson and whatever else it would take to get David Price. Instead they got Gerardo Parra. The trade might have let the wind out of more than a few sails, but it worked out pretty well for the Brewers.
Parra took over the fourth outfielder role previously occupied by Logan Schafer. Schafer provided the Brewers with solid defense, but was absolutely awful offensively. He hit 181/298/276 with a 49 wRC+. According to Fangraphs Schafer was worth -0.1 WAR.
If you were to look at Gerardo Parra's season totals you might think he wasn't much better than Logan Schafer. Afterall, he was only worth 0.1 fWAR. However if you split the season between Arizona and Milwaukee you see a stark contrast. As a starter for the Diamondbacks Parra was worth -0.4 fWAR. But as a 4th outfielder for Milwaukee he was worth 0.5 fWAR.
Parra was worth so much more to Milwaukee because the Brewers were able to utilize him in spots that would give him the best chance to succeed. In his career Parra hit 231/296/292 (59 wRC+) versus left handed pitching. But, versus right handed pitching he hit 286/334/424 (99 wRC+).
Of his 134 plate appearances as a Brewers, only 14 of them came against left handed pitching. As a result he hit 268/318/390 (93 wRC+). Obviously it's not outstanding, but compared to Logan Schafer's offensive contribution the improvement is significant.
The interesting thing is that Schafer and Parra saw almost exactly the same number of plate appearances (136 and 134 respectively) with the Brewers. They also started about the same number of games (29 for Schafer, 28 for Parra). If Parra's value to the Brewers were spread out across the whole season, he might have been worth approximately 1 fWAR. If that were the case, he'd have been almost a 1.5 win upgrade over Schafer.
Gerardo Parra's best game for the Brewers was unquestionably September 1st at Wrigley Field. He got a base hit in 3 of his 4 at bats including a home run. Unfortunately the Brewers were unable to contribute much else to this game and fell to the Cubs 4-2.
Gerardo Parra will be entering his final year of arbitration. As such, the Brewers have the option of tendering him a contract or not. The deadline for that decision is December 2nd. If they nontender him he immediately becomes a free agent.
If they do tender him a contract they will negotiate his salary. If they can't come to an agreement then they will have to go to an arbitration hearing at which time an impartial arbiter will hear both sides and decide on a salary. Arbitration hearings take place in February. The Brewers are usually pretty good about avoiding the arbitration process and so we'd probably hear something sooner than that.
Statistics courtesy of Fangraphs