The Cardinals are in the hunt for their third straight NL Central crown, but it will be interesting to see how St. Louis comprises its postseason rotation.

The Redbirds own an MLB-best 89-54 record entering play Tuesday and a 2 1/2-game lead over the Pirates atop the division with a magic number of 18 to clinch. The Cardinals are looking to reach the 90-win plateau for the third straight season and fourth time in five years and to continue to play deep into October.

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St. Louis has reached the NLCS in the last four seasons, making it to the World Series twice in that span, losing to the Red Sox in 2013 and defeating the Rangers for their latest title in 2011.

The Cardinals have struggled in September, battling injuries and playing to a 4-8 record thus far. Their team ERA has swelled to 5.31 for the month, as the club has given extra days off to rest its taxed rotation. It still appears as though St. Louis will right the ship here in the most important stretch run of the season.

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On the back of strong starting pitching, the Cardinals seem poised for another deep postseason run, despite the fact that ace Adam Wainwright was lost for the year on April 25 due to a torn Achilles. Wainwright has vowed to return by season's end, but even if he doesn't, St. Louis is in great shape.

The Cardinals own the best team ERA in the majors with a 2.87 mark, even with Wainwright sidelined for the majority of the season. Michael Wacha, 24, has stepped up as a de facto ace, ranking tied for fourth in the NL with 16 wins and in sole possession of second with a .762 winning percentage. Overall, he's 16-5 with a 2.96 ERA, 1.153 WHIP, 141 strikeouts and 47 walks.

Lance Lynn has also helped provide the Cardinals with a solid 1-2 punch atop the rotation, pitching to an 11-10 record with a 3.17 ERA this season. Lynn has had his ups-and-downs on the campaign, including a 9.72 ERA this month, but he warrants a spot in the playoff rotation.

To the surprise of many (even despite things always seemingly working out for the Cardinals), John Lackey has stepped his game up after the loss of Wainwright. The veteran right-hander is 11-9 with a 2.89 ERA this season as he looks to finish with a sub-3.00 ERA for the first time in his career.

Lackey also has plenty of playoff experience, owning a 7-5 record in 21 games (18 starts) with a 3.08 ERA while appearing in 14 series.

Carlos Martinez (13-7, 3.12 ERA) and Jaime Garcia (8-5, 2.33 ERA) round out an excellent rotation for the Cardinals. Martinez, however, has struggled lately, posting a 1-3 record an 5.60 ERA in his last five starts. Garcia, meanwhile, owns a 4.76 September ERA.

For the playoff rotation, assuming Wainwright won't be back, it's a tough call determining who the odd man out will be. Wacha should be a lock to spearhead the unit while it seems Lynn should also take a spot. That leaves Lackey, Martinez and Garcia to battle it out for two open spots.

Lackey has struggled against left-handers this season, so if the Cardinals play the Cubs, he could find himself out of the rotation. Lackey also owns a better home ERA than a road one, and it's unlikely he'd start in Games 1, 2 or 5 in the NLDS. Still, as a veteran with experience, he may warrant a start, but for now he's the odd man out of the arms race. If Lynn's struggles continue, however, he may have to be replaced as well.

Assuming the Cardinals hold on to win the division and host the Pirates/Cubs for the NLDS, here is our potential rotation for St. Louis:

1) Michael Wacha
2) Lance Lynn
3) Carlos Martínez
4) Jaime García

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