Over the next several days/couple weeks, I'd like to take a position-by-position look at the Astros, getting a quick overview of the current starters, backups, and minor league players who could contribute this season.
Starter - Jason Castro
Castro is starting to make people think that his 2013 All-Star year may have been his career year, even though he's still just 27. Despite his batting average dropping from even last season's, he's actually made some improvements offensively. His walk rate is up about 2% while he's dramatically cut down on his strikeouts, cutting about 7.5% from last year. He's regained some of his pop and his .237 BABIP this year indicates his batting average could see a rebound. He's even seen a good bump in his caught stealing rate, to the point where he's been above average in 2015. Looking at the most widely used projection systems for the rest of the season Castro is trending towards being a 2-3 WAR player this year. That would make him a middle of the pack starting catcher.
Reasonable end of season projection ranges
AVG - .215-.240
OBP - .285-.315
SLG - .380-.410
Backup - Hank Conger
The trade for Conger still looks like a bit of a head scratcher. We all heard about his pitch framing prowess, but with his limited playing time so far I can't help but wonder how much good that's doing for the club. When you factor in that the Astros gave up Nick Tropeano, a young starter with potential who's turned in one strong start for the Angels this year, and Carlos Perez, a backup catcher who has held his own in the majors so far with almost as much playing time this year as Conger, this one is looking like a needless trade. As far as his performance, 41 plate appearances isn't enough to give us an indication of how he'll perform over a season. His batting average is abysmal, but he's sporting a nearly 20% walk rate and two of his three hits have been home runs, so he's actually close to league average offensively in an extremely small sample size. His .176 BABIP indicates his average will come up, but his track record says his walk rate will come way down so his OBP probably is about right. Projections put him at a .5-1 WAR player by the end of the season, which is a small return for the above mentioned prospects.
Reasonable end of season projection ranges
AVG - .180-.230 (wide range due to small sample size so far)
OBP - .295-.330
SLG - .345-.375
Prospect - Max Stassi
We've heard for a couple years now that the front office thinks of Stassi as the "Catcher of the Future". Barring injury, I don't think he'll get any meaningful playing time until possibly September. Of course, if the Astros are still in the playoff hunt at that point in the year, even that may not happen. He's struggled quite a bit in AAA, especially so far this year, so the bloom may be off the rose with Max. So far this year he's striking out at a pace that would make Chris Carter proud. He's shown an ability to get hot fast in the past, albeit at AA, so I don't think it's quite time to give up on him yet, but this season is pivotal for him. But we'll always have the memory of him getting his first major league RBI by catching a pitch with his teeth.
Prospect - Jacob Nottingham
Nottingham has been creeping up the bottom of the Astros prospect lists the last couple seasons. He's expected to develop into a power hitter, though there's a little concern he may not stick behind the plate. After mixed results the last couple years with the Gulf Coast squad and in Greeneville, Nottingham is off to a strong start with Quad Cities, the best minor league team in baseball so far this year. He's cut down on his strikeouts and his power has been showing up more frequently, as he's currently sporting a .250 ISO, including six homers in 121 plate appearances. He's still a few years away, but behind Stassi he's the biggest hope at catcher down on the farm.
Prospect - Tyler Heineman
Heineman isn't appearing on many prospect lists, but this switch hitting catcher shouldn't be forgotten. In his second season at Corpus he's putting together a solid season. He doesn't look like a power guy, but he's been showing a solid ability to handle the strike zone with a solid walk rate and a very good strikeout rate (just 6.3% so far this year, 12 % last year). Defensively, he has a strong 43% caught stealing rate so far. He's not the kind of prospect you can dream on, but he could turn into a solid player.
Depending on the rest of Stassi's season, it looks like Castro is still the catcher of the next few seasons. He'll get more expensive as he works his way through his arbitration years, probably ending up around $8-10 million per season. If he can continue to produce between 2 and 3 WAR per year, that's about right. Conger is just as much of question mark as he was at the beginning of the year. Stassi may be playing his way out of his prospect status and Luhnow's Christmas card list and Nottingham is too far away to expect anything soon. I'd grade the Astros overall catcher situation as a C+.