It's hard to imagine the Cardinals without Yadier Molina. Yadi has been with the Cards since he was called up in 2004 to serve as Mike Matheny's back-up. From 2005 on, the least PA Yadi had in any year was 396. The Cardinals have gone to the playoffs 8 times in those 11 years, only missing them in '07, '08, and '10. They've also won two World Series, appeared in another, and played in a total of six NLCS series.
Three of those years were pretty incredible. From 2011 to 2013, Yadi was worth nearly 16 wins (just over over half of his career WAR). That led the league over that time frame. In terms of wRC+ among catchers, Yadi was only beaten out by Buster Posey and Mike Napoli, who is listed as a catcher but was being moved off the position during that time frame, and hasn't caught at all from 2013 onward. In terms of Defense, Yadi was second among catchers in Def (defensive runs above average) to only Matt Wieters.
That was only his peak, but even when he wasn't great on both sides of the ball, he's always been here contributing. From 2005 on Yadi has been worth 30.5 wins, an average of just under 3 a year. With Yadi entering his age 33 season, it's fair to wonder, where are the Cardinals going to get this production from after he's gone?
The best internal option is VEB's 15th best Cardinals prospect, Carson Kelly. Kelly isn't a non-prospect or anything, but it's also a little hard to imagine him being at least an average MLB starter at this point. Kelly gets rave reviews behind the plate, which is great considering the Cardinals value defense and he just moved to the position in 2013. But at the plate is a different story: Kelly slashed just .219/.264/.332 this year, but it was also in a very pitcher friendly environment. That still only earned him an 80 wRC+, though minor league wRC+ is just adjusted for league, not park.
The bat tends to develop slow for catchers because of all the extra work they have to do. So there's that. But we also shouldn't simply count on Kelly to step right in once Yadi is done. There's also #20 prospect Mike Ohlman, but he's on the list almost entirely because of his proximity to the majors (he should start the year at Triple-A). His value is in being a back-up the next few years, not in replacing a franchise cornerstone.
The free agent market doesn't offer many alternative either. Yadi is guaranteed another two years, plus an option year. The 2017-2018 free agent market is headlined by Miguel Montero, Francisco Cervelli and Jonathon Lucroy. Lucroy is an interesting option but Montero could be fairly washed up by then as he would be 35 by the time he reaches free agency.
Looking ahead to 2017-2018 and there's Derek Norris and Yasmani Grandal, two interesting options. But short of that there's not much to look forward too. Perhaps the Cardinals will have to end up trading for their future catcher. Looking at KATOH's Top 100 there is Jacob Nottingham of the A's at #15, Wilson Contreras of the Cubs at #20, Chance Sisco of the Orioles at #22, Dom Nunez of the Rockies at #28, Reese McGuire of the Pirates at #46, Tyler Heinemen of the Astros, Andrew Knapp of the Phillies, Gary Sanchez of the Yankees at #58, and Austin Barnes of the Dodgers at 66, with Carson Kelly coming in at 87.
Team's don't generally trade catching prospects, and the Cubs and Pirates probably aren't wanting to trade with with the Cardinals. The A's just traded for Nottingham and they might value his services pretty highly. It's hard to say if the Astros would even consider trading with the Cardinals, and the Yankees have long denied including Sanchez in deals. It might be very difficult to make a trade at all for one of these guys, and if it was possible it would probably take a high price.
What will the Cards do? There really doesn't seem to be an easy answer. The Cardinals basically have to hope Carson Kelly improves, eventually sign a catcher at free agent prices, or trade Major League pieces for a catcher of the future. The last two come with high price tags, and the first may just be wishcasting. Kelly could end up being great, or he could end up never having a starting role in the majors. He's a nice piece to have, but you'd really like to see more than that in the pipeline.
I for one will be interested in what the Cardinals, who typically think long-term, end up doing with this situation.