Beltran versus Carpenter versus Pitchers

The Cardinals have a pretty commanding 3-1 series lead on the Cardinals, but it is far from a done deal yet. Even if they do win the series in the next three games, the Tigers and their pitching staff, which just dominated the Yankees, are waiting. St. Louis potentially have 10 games left this season. While even over 10 games, one starting position player being out does not usually make much of a difference, it does make a difference. Given the stakes, teams obviously need to have all hands on deck. Matt Carpenter has done a nice job filling in for Carlos Beltran since the latter tweaked his knee earlier in the series. Beltran is hoping to start, but if he can’t tonight or in the near future, how much is it likely to hurt their offense?

Beltran has had an up-and-down year at the plate. He was very hot in the first half of season, then put up sub-.300 wOBAs in July and August. He rebounded in September and has spent the playoffs reminding people that, yeah, despite that one memorable strikeout, he has been awesome in the postseason during his career (.375/.486/.830, 234 wRC+ in 138 plate appearances) — something worth remembering when considering his Hall of Fame-worthiness. Over the last four seasons, Beltran’s numbers have been up and down. However, while his 125 wRC+ is down from last year’s 152 wRC+, his power is still there. Oliver forecasts Beltran’s current true talent wOBA at .376.

While there is some question as to how Carpenter will fit into the Cardinals lineup in 2013, for now he just isjust another example of the Cardinals’ depth. Oliver sees Carpenter’s current true talent wOBA as .346. Leaving aside any fielding difference between having Allen Craig in right field (with Carpenter taking his place at first) rather than Beltran, a difference of thirty wOBA points is pretty big. Over a full season, that is worth would be about 15 runs. Of course, over the maximum possible ten games left in the Cardinals’ season, it is projects to be less than a run. But relative to most things over ten games, that is a relatively big difference.

The difference is actually bigger in the (very) short-term. Tonight, the Cardinals are facing lefty Barry Zito. Leaving aside Zito’s own splits (since we are focusing on the hitters), Carpenter is a lefty and Beltran is a switch-hitter. While a few years ago it looked like Beltran was turning into a switch-hitter who did most of his damage versus lefties, he last couple of seasons he’s been closer to his career split. For his career, Beltran has hit southpaws about 14 wOBA points better than righties. Switch hitter platoon splits stabilize more quickly than for other hitters, and Beltran has many career plate appearances versus lefties. We should still regress using this method). Applying his estimated platoon split to the Oliver projection listed above, he projects as a .386 wOBA hitter versus lefties.

Carpenter’s observed split so far in the majors is pretty small compared to most lefties. However, he only has 107 big-league plate appearances versus lefties, so his projected split regresses almost all the way to league average (again, read this for more details). Basing the overall projection on the Oliver forecast, Carpenter projects as a .325 wOBA hitter versus southpaws. That is slightly above overall league average these days, but is still a pretty big gap. Over a full season, that would be about thirty runs. To put it in a different light: there is a 60 point projected wOBA difference between Beltran and Carpenter versus lefties; there was a 55 point difference between Matt Holliday and Skip Schumaker’s 2012 wOBAs. So it is a pretty big loss, relative to other losses. Yes, it is only one game, but very few things make much of a difference over one game.

Beyond just the game, however, the story changes. If the Giants end up taking the Cardinals to Game Six and/or Seven, the projected starters, Matt Cain and Ryan Vogelsong, are both right-handed pitchers. If St. Louis gets to the World Series, all four of Detroit’s starters are right-handed. While it sounds like Beltran might be able to play tonight, we also know that these sorts of things can drag on. How big of a difference would it be versus right-handed pitching? The projection method used above estimates Beltran’s true talent wOBA versus right-handed pitching to be .372, and Carpenter’s to be .355. So Beltran would still be clearly preferable (assuming Oliver’s initial projection is in the ballpark for both players). That much we could have gotten, one might say, simply from the non-platoon projection. However, the overall difference was about 30 points, while the difference versus right-handed pitchers (all of the starters the Cardinals project to potentially face after tonight’s game) is about half of that. It is a loss, but not as big a loss as it would seem without looking at upcoming potential matchups.

So, yes the Cardinals are probably better off with Beltran at the plate than Carpenter. However, we need to keep things in perspective. To have a player like Carpenter available to replace an Beltran is a luxury few teams have. I cannot imagine that many teams would rather be in a position where they would have to start, say, Quintin Berry, because of an injury. Moreover, after tonight’s game, matchups also work to make Carpenter more valuable if he is needed to fill in for Beltran. The difference may be small, but in the playoffs, the stakes are high. Once again, the Cardinals’ superior depth works in their favor.