So the Cardinals have had to deal with everything from nagging shoulder separations, barking knees, tweaked hammy's and right out of the gate, calf strains. And that doesn't even count Kyle McClellan and Skip Schumaker! Even Yadi was out for a brief stint. That's kind of a staggering amount of injuries, yet the Cardinals are still in first place.
This is in great part due to Rafael Furcal's torrid start to the season, OPS'ing nearly .930 at shortstop. In fact, he has been the best shortstop in MLB so far this season. That's not to say he will continue doing that, since his BABIP is at .400. That said, he has been all or more than what you would want for a leadoff hitter. The main concern is him continuing to stay healthy, of course. But so far he has not been a worry.
The other factor being Carlos Beltran. Essentially, this duo were signed to replace Albert Pujols, and they have been far more than capable in almost a quarter of a season. By weighted on-base average, Beltran's peers are Matt Kemp and Josh Hamilton. So he has been a top 3 hitting outfielder, and right around 6th best in MLB (basically the same as Joey Votto). Perhaps most impressively, Beltran is tied for second in home runs in the majors... even while missing the last few games; AND, his BABIP is ridiculously normal at .299.
And let's not forget slow-starting Matt Holliday, who is now at .352 wOBA prior to tonight's game (where he hits a home run). With Beltran's 13 home runs and Holliday's 8 or 9 or so, that is a nice core of the order as one would expect of these two players. Of course, Yadi's hot start cannot be overlooked: .386 wOBA; .303 BABIP. And the ridiculous potential of the often milk cartoned Allen Craig, sporting a 218 wRC+ and tied for third on the team in home runs in very limited playing time.
As a team, the Cardinals have amassed 13.3 WAR, easily the most of any team. AL world series contender the Rangers are second with 11.2, and the other NL powerhouse, the Braves, are at 10.1. Current series rival the Dodgers are also really good, at 9.6, 4th best team in baseball by WAR. So we should see a pretty great series.
Taking some components out of the equation and focusing on offense sabermetrics, the Cardinals are still best by wRC+ and wOBA. However, the Rangers are much better at fielding so far, as detected by the UZR systems. Defensively, the Dodgers, Rangers, Mariners, Diamondbacks, and Angels are the best, with the Cardinals in the middle of the pack.
Pitching-wise, the Cardinals fared quite well at 3.43 FIP. By ERA they have been not nearly as effective, but they place third in xFIP. While they have been in all probability overachieving, it is nonetheless an encouraging start. As usual, the Cards lead the NL in GB%. The Cards (and Cubs) have been worth the 4th most WAR for starting rotations. The Cardinals rotation nearly stacks up with the Nationals and the Phillies for best in MLB FIP. The starting rotation is right at .300 BABIP, so it seems somewhat sustainable.
That said, the Cards' bullpen this year has been rather shaky so far. The bullpen guys stack up right in the middle of the league in FIP, but the eleventh worst by ERA at 4.03. Perhaps the most alarming thing is that the BABIP of the relievers is .270, which could mean at the very least a middling regression. Given a somewhat limited payroll, Mozeliak assembled the bullpen pretty well, as it is not really liability. And by jettisoning JC Romero, J-Mo showed some quick wits (probably since he was burned last year by a similar situation).
Perhaps surprisingly to many fans, Mitchell Boggs has been the most effective reliever, despite a .326 BABIP against and some mishaps in the field by his teammates. Motte has also done extremely well, giving the bullpen a certain bearded character or identity. With Romero gone and McClellan out, the bullpen will in all likelihood stabilize.
Contrary to previous seasons, the Cardinals are no longer a slow team. In fact, so far at least by Fangraphs' Spd rating, they are tied for the fastest team in all of baseball. To sum up, the Cardinals have been getting on base a lot (1st, .352) AND making solid contact (tied with Yankees for 2nd behind Orioles at .186 ISO) while flashing some quick speed. Lastly, Cardinals hitters are a well rounded group except against the slider, which seems to be their main weakness as a team.