The Brewers created a need at catcher when they traded Jonathan Lucroy away at this year's trade deadline.
They may have addressed that need minutes later when they got Andrew Susac from the San Francisco Giants as part of the return for Will Smith, but he'll be 27 next year and doesn't have much big league experience. Martin Maldonado did fine as a full-time player after the Lucroy trade, but he's also been a career backup. If we're looking for areas where the Brewers could use an upgrade, catcher would probably be one.
Which brings us to Jason Castro, one of a few catching options in the free agent market this winter.
To be blunt, Castro stunk in 2016. He's stunk for a few years, actually, hitting .215/.291/.369 over the past three seasons in Houston with an OPS+ of 84. He's posted wRC+'s of 86, 79 and 88 over the past three years. If you want a point of comparison, Jonathan Lucroy's wRC+ this year was 123.
He's also struggled with strikeouts over his career, and has seen the whiffs increase during this three-year dry spell. He's struck out in about 30% of his plate appearances during that time, and saw that number creep towards 33% this past season. Astros fans weren't guaranteed much this year, but if they went to a game, they were seeing at least one Castro whiff.
As bad as the overall numbers look, his numbers against left-handed pitching are even worse. As a lefty himself, he's hit a Scooter-like .190/.249/.287 against like-handed opponents for his career. Any team that signs him might want to consider a platoon as a way to give him a day off here or there while also hiding his ineffectiveness against lefties.
But Castro hasn't always been this bad offensively. In fact, he was an All-Star in 2013, when he hit .276/.350/.485 with 18 home runs and 35 doubles. The fact that he's shown the ability to hit well (really well for a catcher) before, is regarded as a very good pitch-framer, should still be in his prime (he'll be 30 next season) and could come cheaper than Wilson Ramos or Matt Wieters is probably why he's drawing a lot of interest already.
He also does do some things well, I swear. As mentioned, he has a very good defensive reputation, and the metrics like his defense enough that he's been worth roughly 1 (or more) WAR every year since his rookie season. He's also hit double-digit home runs for four years straight, and saw his BB% improve by more than 3% this year.
According to MLB Daily Dish, six teams are reportedly already interested, including the Astros, Braves and Twins (the Brewers have not been linked to him at this point). Early projections had him fetching $7.5 million or so per year on the open market, but that level of interest could end up drawing a 3+ year deal and an average annual salary that could be tough for a small-market rebuilding team to swallow.
While the Brewers may be content seeing what they have with Susac and Maldonado, as some suggested with or “Tender or Non-Tender” series, maybe there could be a trade market for Maldonado if a contending team is looking for plus-defense at a cheap rate. In that case, maybe the Brewers would be able to swing a Castro/Susac platoon -- the latter has mashed lefties during his extremely limited time in the majors, and could see a couple starts per week in that role.
There are plenty of other veteran catching options out there this winter, but Castro would represent an interesting buy-low opportunity for any team hoping he could regain his All-Star form.
Statistics courtesy FanGraphs and Baseball Reference