Don't expect Cardinals' reign atop NL Central to come to an end in 2015

This week, SI.com is previewing all 30 MLB teams, counting down to the No. 1 team in the league. At No. 6: the St. Louis Cardinals.

2014 Record and Finish: 90–72 (.555), first in NL Central (sixth overall)

2015 Projected Record and Finish: 91–71 (.562), first in NL Central (sixth overall)

The Case For

Last season, the Cardinals went to the playoffs for the fourth straight year (and fifth of the last six) before losing to the eventual World Series champion San Francisco Giants in the NLCS. And if anything, St. Louis should be somewhat improved in 2015. The Cardinals bolstered their outfield and lineup by trading pitcher Shelby Miller for Jason Heyward (a move that could easily haunt the Braves for a good, long while), who even in a bit of an off-year put up a WAR of 6.3, which would have been the top mark for St. Louis.

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​Heyward was so hyped as a prospect that he earned the nickname “Baseball Jesus,” and while he didn’t quite live up to that moniker—he’s hit a very good but not Mike Trout-ian .262/.351/.429 over his career with an OPS+ of 114—he’s nevertheless a consistently valuable player and is still only 25. He joins promising youngsters like Matt Adams and Kolten Wong, veterans Jhonny Peralta and Matt Holliday, and on-base machine Matt Carpenter to form what should be a solid core.

Meanwhile, the pitching staff that was the foundation of the team’s success last year returns, with the exception of Miller, led by a hopefully healthy Adam Wainwright and Michael Wacha (see below), innings-eaters Lance Lynn and John Lackey, and whoever wins the battle between a resurgent Jaime Garcia and up-and-comers Carlos Martinez and Marco Gonzales for the fifth spot. There’s no reason to think we aren’t in for another tiresome debate over whether St. Louis fans are the best in the game come October.

The Case Against

If there’s one area the Cardinals could stand to improve, it’s their bullpen. Though not a Tigers-esque Achilles heel, it was still 10th in the NL last year in ERA (3.62), and that was with their best reliever, Pat Neshek, who departed for the Astros over the winter. Closer Trevor Rosenthal’s walk rate jumped from 2.4 in 2013 to 5.4 last summer en route to a not-great-for-a-closer 3.20 ERA (though he's only 24, so there’s no reason he can’t bounce back). As for the new additions, Jordan Walden, who came over in the Heyward trade, had a strong '14 for the Braves but will need to reduce his own 4.9 BB/9 rate, and free-agent signing Matt Belisle has been declining for the last three years. The Cardinals still have 39-year-old lefty specialist Randy Choate, but they spent the winter trying and failing to trade him, which isn't exactly a vote of confidence.

With so many strong arms in their system, the Cardinals should be able to find enough pieces to put together a capable 'pen (likely including at least one of the losers of their No. 5 starter competition). But the NL Central is a tough division these days, and St. Louis could use every win. It’s hard to see the Cardinals missing October altogether barring a downright biblical injury plague, but a few blown saves in April and May might mean the difference between a wild card spot and a division crown.

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​X-Factor: Michael Wacha

Wacha’s injury last season was a relatively unusual one in baseball: a “stress reaction” in the scapula bone in his right shoulder, which can be the precursor to a stress fracture. The most famous recent example is similarly tall and reedy Dodgers pitcher Brandon McCarthy, who has lost parts of four seasons to a pitching shoulder stress reaction—something Wacha and the Cardinals would obviously like to avoid. Still just 23, Wacha has a 3.04 ERA in 171 2/3 professional innings and a strikeout-to-walk ratio of 2.85. The Cardinals have pitching depth—the players who don’t get the No. 5 nod out of the gate could step in if needed—but they are a more imposing team with Wacha.

Red Sox, Mets, Cubs among potential playoff surprise teams for 2015

A close X-factor runner-up: Wainwright. Although he had yet another fantastic season—2.38 ERA, 6.1 WAR—his strikeouts were down a tick, and he flagged in the postseason. His off-season arthroscopic elbow surgery was relatively minor, but since returning from Tommy John surgery in 2012, Wainwright has thrown 733 1/3 innings, including the playoffs, more than any other MLB pitcher. That’s both a testament to his durability and, depending on your level of paranoia about pitcher health, perhaps an ominous accomplishment for a 33-year-old. Losing him could ruin St. Louis' hopes; even the Cardinals don’t have pitchers that good just lying around.

Number To Know: 105

That was the Cardinals’ 2014 home run total, dead last in the NL and ahead of only the Royals’ 95 in all of baseball. Of course, that didn’t exactly cripple either St Louis or Kansas City, and not coincidentally, those teams also struck out the least often in their respective leagues. But overall, the Cards were middle-of-the-pack in offense and below league average in runs scored (with 619), so they could certainly use a power boost.

Peralta led the team with 21 homers in 2014, but he doesn’t consistently hit that many, and while Holliday does (he posted 20), he’s now 35. The Cardinals will need more pop from the younger generation. Heyward should help—though he’s not really a traditional slugger, he did belt 27 in '12—and also could use strong seasons from infielders Adams and Wong, both of whom have another year of learning the strike zone and adjusting to major league pitching under their belts.

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Scout's Takes

Most Overrated:Jhonny Peralta, SS

"He can be pitched to in certain situations. Don't give him anything in the middle of the plate; I'd give him soft breaking balls. You can tie him up inside, and he's very aggressive early in the count."

Most Underrated:Kolten Wong, 2B

"There are so many other guys around him, I don't think people notice him until it's too late. He needs to tone it down just a tad and understand the zone a little more, but he's got pop, speed and provides a little bit of everything on the field. That will allow him to have a big breakout."