How does the St. Louis Cardinals' core compare to the rest of MLB?

The St. Louis Cardinals have been bandying about the word "core" as an adjective to describe ballplayers going back to the days when Walt Jocketty was the organizaiton's general manager. Most infamously, at least in my mind, was when the Cardinals signed Juan Encarnacion to take over right field from Larry Walker. Jocketty described Encarnacion, who had posted a 97 OPS+ up until that point in his career, as a "core" player. As we entered 2006 (a season in which Encarnacion would put up a batting line that equaled a 93 OPS+) it seemed that the term core had lost all meaning.

In recent years, though, the term has been reinvigorated somewhat. General manager John Mozeliak uses it on occasion. As does the media. Typically they are referring to players like Adam Wainwright, Matt Holliday, or Yadier Molina. Allen Craig was a core player until he couldn't hit and the club traded him to the Red Sox. Matt Carpenter earned the tag after his MVP-caliber 2013. Now they are talking about Jason Heyward as a new core member, which makes perfect sense.

This offseason, we have written a little bit about the Cardinals' aging core and talked about it on the podcast. Holliday (35), Peralta (33), Wainwright (33), and Molina (32) aren't getting any younger. On the wrong side of 30, each are entering the downslope of their respective careers. The window to win while counting on these players as core contributors is not going to be open too much longer.

This got me to wondering how old every other major-league club's "core" is entering the 2015 season. After all, if other clubs are relying on players as old or older as those the Cards are relying on to be key contributors, is their age a problem? Probably not. But if every other club is relying on players quite a bit younger, the Cards might find themselves fading and get surpassed by the pack.

Performing this comparison posed a problem: How to define "core" for purposes of this exercise? I decided to use a forward-looking approach. I went to Fangraphs and looked at the 2015 ZiPS projections for each club. I decided to use a narrow definition of "core," so I took the top five players—pitchers and position players—in projected Wins Above Replace (zWAR). WAR is not perfect, but for the purposes of this inquiry, it is as good as any other way of determining who is likely to be a club's top producer. Five is an arbitrary number, but expanding it beyond 20% of the active roster seemed to be getting expansive. This means some players are left out of the core calculation due to a tenth or two of projected WAR.

Using this method, here are the Cardinals' five core players, according to ZiPS, as we enter the 2015 season:

1. Wainwright (Age 33, 5.0 zWAR)
2. Molina (Age 32, 4.5 zWAR)
3. Heyward (Age 25, 4.4 zWAR)
4. Lynn (Age 28, 3.8 zWAR)
5. Peralta (Age 33, 3.7 zWAR)

On the outside looking in, thanks to the acquisition of Heyward, are Carpenter and Holliday. This is not because ZiPS forecasts either player to be bad. In fact, ZiPS projects Carpenter to put up a 3.2-WAR season and Holliday to post 2.9 WAR. Indeed, if they were on another team, they likely would be core players because other teams don't have five players who project to be as good as Wainwright, Molina, Heyward, Lynn, and Peralta, according to the ZiPS forecast.

Even excluding the 35-year-old Holliday, the average age of the Cardinals' core is 30.2, which is pretty old relative to the rest of the majors. The St. Louis core has the fourth-highest average age among the 30 clubs. The Cardinals' also project to have a productive core. Their 30.2 zWAR are the fourth-highest as well, tied with Toronto. Their combined salary is the sixth-highest core salary in baseball, and the Cards' $/WAR ranks eighth.

I put together a chart that is ordered by average core age. It also includes the total core zWAR, salary (using the wonderful Cot's Baseball Contracts), and cost per WAR. When looking at it, keep in mind that some teams' highest paid player (or players) are not projected to be a top-five contributor on their club. For example, Alex Rodriguez, CC Sabathia, and Mark Teixeira, the three highest-salaried Yankees, are not forecast to be in the club's top five, per ZiPS.

2015 MLB Cores by ZiPS

Here's an embed of the team-by-team core breakdown, including the individual players for each club (and link since the embed is tiny):