Part of the reason that the Cardinals signed Matt Holliday to a seven-year, $120 million contract this winter is that they needed help in the outfield. While there was plenty of promise out there, the team couldn’t exactly count on results for 2010. Ryan Ludwick had just posted a disappointing follow-up season to his 2008 career year, and Colby Rasmus was still an unseasoned 23-year-old. They needed solidity out there, and that’s why they retained Holliday. When they then got superior production from Rasmus and a rebound from Ludwick, the Cardinals boasted one of the top outfield units in the league.

All three outfielders have produced numbers that are well above league average. Holliday unsurprisingly leads the bunch with a .397 wOBA, though Rasmus isn’t far behind at .381. Ludwick, after seeing his wOBA drop from .406 in 2008 to .336 in 2009, is back up to .352. Those three have covered the easy majority of the season at their positions; no other Cardinal has more than 72 PA as an outfielder. It came as a disappointment, then, that Ludwick hit the DL retroactive to June 26 with a strained left calf. But given his primary replacement, the Cardinals aren’t missing his production very much.

Jon Jay was having a reasonably successful season after the Cardinals called him up in late April, hitting .302/.302/.442 in 45 PA. The obvious weakness is that he drew zero walks in that span. His .364 BABIP suggested that he’d hit considerably below that level if given an extended look. Apparently they saw that, too, and decided to sign Randy Winn, whom the Yankees had released in May. Jay was the roster casualty, sent back to AAA so he could continue his hitting display against PCL pitchers. But when Ludwick hit the DL in early July, the Cardinals called Jay’s number again.

The Chief Justice has gone on a tear in Ludwick’s stead, producing a .539 wOBA since his recall. That brings his season wOBA to .429, though in a mere 86 PA. Of those, 41 have come since July 3, which seems like a low number. That’s because Tony LaRussa has kept him in a pretty strict platoon. Only six of his PA this season have come against righties. Under normal circumstances a platoon would work to Jay’s advantage once Ludwick returns, and since LaRussa has said that Jay will get enough at-bats later in the season, a platoon might seem likely for a lefty-righty outfield combo. But given Ludwick’s performance, that might not be the best idea.

Ludwick is one of a rare breed, along with Cody Ross and Rickey Henderson, who bats righty but throws lefty. But while the other two perform like typical RHB in that they hit LHP far better than same-handed pitchers, Ludwick has a reverse platoon split. The difference is pretty stark in 2010, a .374 wOBA against righties and a .300 mark against lefties, but it has been that way for his entire career. In 1293 PA against righties he has a .369 wOBA, while in 634 PA against lefties he has a .333 wOBA. He is not, then, an ideal player to platoon with Jay, who possesses a typical lefty split. In the minors he had roughly a .311 wOBA against lefties and a .364 mark against righties.

In fact, creating any type of platoon with Jay and another outfielder probably wouldn’t work, as they all hit righties exceedingly well. Rasmus, also a lefty, has crushed RHP this season, a .266 ISO that factors heavily into his .388 wOBA against them. Even last year, when he hit relatively weakly overall, he produced a .341 wOBA against righties while managing just a .218 wOBA against lefties. Holliday hits everyone well, though against righties this year he’s faring slightly better, a .395 wOBA vs. a .391 mark against lefties. That split, too, holds up over his career, as he’s produced a .402 wOBA against righties and a .378 wOBA against lefties.

(Not that either would face a platoon anyway.)

Jay has been a useful player since his recall, filling in for Ludwick better than anyone could have reasonably expected. When, then, will LaRussa find playing time for him when Ludwick returns this weekend? It might not actually be that big an issue. After all, it’s not as though Jay was some superstar prospect waiting for a spot to open. Baseball America did rate him as the Cardinals’ best minor league hitter for average, but did not rank him in their top 10. Nor did Marc Hulet. We’ve seen this plenty from young players before. They come up and mash for a while before reverting to their expected forms. Thankfully for the Cardinals, Jay’s hot streak comes as he fills in for an injured player. You can’t ask for much more than that.

The Cardinals do have a few options to face LHP, Winn and Nick Stavinoha, though Winn has been stronger against RHP in his career and Savinoha hasn’t hit very well in general. Somehow I don’t think that will become much of an issue. The Cardinals get plenty of production out of Holliday and Albert Pujols against LHP, so I’m sure they’re perfectly content with their righty-mashing outfield trio. Jay has been the perfect fill-in, and will remain a solid reserve and pinch-hitting option for the remainder of the season. As for finding regular playing time, though, I’m not sure it’s in the cards. The current starters can do what Jay does plenty well. It sounds like a pretty favorable situation in St. Louis.