Yadier Molina is the most indispensable Cardinals player

Heading into last season, I had very high expectations for Yadier Molina. He was my pick for National League MVP. He was coming off three great seasons in a row. He had averaged nearly six fWAR over the previous two years. Buster Posey had recently won an MVP as a catcher, and the defensive aspects of Molina's game were gaining in appreciation. Molina did not end up winning that MVP. The Cardinals made the playoffs and Molina had a solid first half, but an injury took away much of his second half. When he returned behind the plate, his play at the plate was behind. Given those issues and the addition of Jason Heyward, I thought that heading into 2015, Molina might not be the Cardinals' most important player. The evidence says otherwise.

Over at JABO, Eno Sarris went looking for most baseball's "Most Irreplaceable Players". He began with the FanGraphs Depth Charts. Here was the methodology:

Let's pro-rate everyone's WAR to 600 plate appearances so they are on the same footing. We used decimal points with the projected WAR just because we have to -- there'd be a lot of backups with zeroes otherwise.

Now all we have to do is subtract the backup's WAR/600 from the starter's number, and we'll get a list of the least replaceable players in baseball.

Yadier Molina did not make first on the list, but he did make the top six. I recommend reading the full article, but here is what he had to say about Molina.

The Cardinals actually did okay last year, and Molina did miss time. But he still managed two-thirds of a season, and all sorts of weird things happened when he was out. Pitchers got worse, for one. And the Cards lost the second-best offensive catcher of the past eight years (the rest aren't catchers anymore). This is mostly about the four-win Molina brother, and not so much about Tony Cruz, who does his best.

The last part is telling. Big things are expected of Molina, but nothing is expected of Tony Cruz. The Cardinals' backup catcher did not play well last season in Molina's absence and caused the team to search for alternatives during the season. The team decided that A.J. Pierzynski was a better starting alternative to Cruz, but have decided to bring back Cruz again to backup Molina. Even if the Cardinals had a slightly more serviceable backup, Molina would still be difficult, if not impossible, to replace. In this season's Positional Power Rankings at FanGraphs, the Cardinals rank fourth despite getting no wins above replacement from Cruz. Molina aged another year, but his projection is still the second highest among all the catcher's in baseball, behind only Buster Posey.

We can repeat Eno's methodology for all the Cardinals. Like Molina with Cruz, how replaceable a player is dependent on the quality of the backup. Projecting bench players over the course of a season is difficult, but we can get a pretty good idea of what those players might look like if given a season's worth of plate appearances.

It is not surprise that Molina heads the list, nor is it a surprise that Heyward is second. Those players are projected for the two highest WAR on the team. Peralta comes in at third, but the big surprises are Carpenter at fifth and Holliday at eighth. I would first note that the difference between .2 WAR when talking about pre-season projections do not carry a lot of weight. They are pretty close to the same.

There is the difficulty in the projections regarding having a full season of several of these players at these positions. We may have a pretty good idea what Kozma can do at shortstop, but we do not know a whole lot about how he would fare during the season at second base. Likewise with Mark Reynolds. Due to the positional adjustment, he is pretty close to a replacement player at first, but nears average at third. His defense at third base may be a tad optimistic. Whether Bourjos could still save enough runs at a corner position to negate the positional adjustment and his deficiencies on offense is not entirely clear because we do not have a lot of evidence to point to how he would do out there. While the Cardinals have clearly made their choice in center field, and Bourjos has yet to prove his health or that his batting projections are realistic, there is some evidence to indicate that he might be the better player in center field if Jay cannot reproduce his solid 2014 batting line.

I do believe the Cardinals have overworked Molina to some degree. I hope he would not get near the 600 plate appearances referenced above, or play any at first base, which is a thought gaining support. However, he remains the most indispensable Cardinals player for 2015.