Nearly all the invitations to the October party have been delivered, but some particulars are still very much up in the air with playoffs set to begin next week -- you know, little things like who's playing whom, and who's playing where.

Details, details.

As usual, the postseason picture isn't complete as the final Saturday of the season hits, and it'll take a few different games at a few different venues to sort it all out, including those last two invites.

With the Pulse of the Postseason continuing its constant drumbeat into the concluding weekend of the season Friday, the tightest division race in baseball finally has a champion with the Cardinals taking the National League Central, and the American League Wild Card race got a little bit tighter, still.

A lot could be answered Saturday, but there's also the strong possibility the field won't be set until the season's final day Sunday -- or perhaps beyond that.

In the NL, we know the Braves and Cardinals will have home-field advantage in the Division Series, but we're unsure which will have the advantage in the Championship Series round. Ditto for the Red Sox and A's in the AL, both assured the advantage in the Division Series, still to be determined in the LCS.

With a lot still up in the air, there was a well-deserved celebration Friday, as the Cardinals wrapped up what has been a tremendous three-horse race in the NL Central with their first division title since 2009, beating the Cubs, 7-0.

"We wanted to win the Central," said Cardinals starter Lance Lynn. "We had to face that Wild Card Game last year, and it's not a fun game to be a part of. You have two good teams that are deserving of being in the playoffs in that Wild Card Game and only one wins. We didn't want to be a part of that."

The Cardinals wrapped up not only the division with their win, but also ensured that the Dodgers will be the No. 3 seed in the playoffs.

Meanwhile, their division compatriots were engaged in Round One of the Wild Card showdown in Cincinnati. It went to the Pirates, who used a two-run single by Marlon Byrd to go ahead and a two-run blistering homer by Pedro Alvarez to stay ahead, marking the 35th homer and 99th RBI for the Bucs third baseman.

Add eight stellar innings from veteran A.J. Burnett, and the Pirates got off to the kind of start to the weekend they hope sets the tone for October.

"I'm just looking for him to pitch three, four more weeks for us," Pirates manager Clint Hurdle said of Burnett.

Friday's victory means the Pirates need one more win in this series to claim home-field advantage for the Tuesday NL Wild Card game we now know for sure these two teams will play.

In the AL, the Wild Card race is providing the reason the field isn't set, with leader Tampa Bay snapping a seven-game winning streak to fall into a tie with the Indians, who won their seventh in a row Friday. Both clubs hold a narrow one-game lead over the victorious Rangers.

The Indians jumped out like they're wanting to take the Wild Card race by the horns, racking up three doubles and a triple in a four-run first, building from there for a 12-6 win over the Twins that raised them into a tie for the top spot in the Wild Card standings.

The Rays jumped ahead, too. But the Blue Jays put together six runs on five singles to take the lead and never looked back, ending the Rays' strong run with a 6-3 victory at Rogers Centre that included some uncharacteristic defense for Tampa Bay, which committed a season-high three errors.

Meanwhile, the Rangers had work to do against their AL West rivals, the Angels, and they got the job done at home. Their midseason offensive addition paid off in this one, with Alex Rios delivering the go-ahead RBI in the seventh inning of a 5-3 victory.

Said shortstop Elvis Andrus: "We just have to keep fighting the way we are doing. All we can do is keep winning, hope somebody loses and we get a shot. We just have to stay focused and wait for that opportunity."

The combination of outcomes left the AL Wild Card in a lovely bit of disarray with only two days left to work it out.

The Red Sox put a 12-3 wallop on the Orioles and the A's ran away with an 8-2 win over the Mariners to keep the AL's best record unsettled, and the Braves stayed even with the Cardinals with a victory in Atlanta, doing it the old-fashioned way -- one homer, and the heat.

After Kris Medlen twirled a gem against Cliff Lee, it was a solo shot by Chris Johnson in the bottom of the eighth that put Craig Kimbrel on the mound for the ninth. As usual, that spelled victory for the Braves as Kimbrel notched his 50th save of the season, joining John Smoltz as the only Braves pitcher to have hit that mark.

"The ball is in our court," Johnson said. "That's nice because you don't have to worry about what other teams are doing."

* * *

The final Saturday of September will provide some level of certainty about the 2013 postseason field, but just how much remains to be seen.

As the Pulse of the Postseason ticks into the second-to-last day of the season, it's possible the entire field could be decided, but the exact configuration of the two five-team tournaments to reach the World Series remains a puzzle.

With two days remaining, the AL Wild Card race for two spots has three teams within a game of each other, both leagues await a top seed and the NL Wild Card Game still doesn't have a home.

The Rays and Indians are both on the road as they take their shared Wild Card lead into the weekend, but the Rangers are at home. Tampa Bay continues its series in Toronto and Cleveland is at Minnesota again, while Texas hosts the Angels.

In the NL Wild Card, the Pirates could ensure themselves of the home field in Tuesday's game with a win at Cincinnati, but a Reds win means Sunday's game would determine that.

In terms of the top seeds in each league, the Red Sox hold a tiebreaker over the A's, and the Braves have the same over the Cards in the same scenario. But Saturday's games, with the Red Sox at Baltimore, the A's at Seattle and the Braves hosting the Phillies and the Cubs hosting the Cards will tell a lot more about where those are headed.

For the Cardinals, who celebrated a division title Friday night, getting that top seed would be something they'd gladly take if they do what they intend to do -- win every game.

"That wasn't necessarily on my goal sheet, but my goal sheet does have us going out to play every game to win," manager Mike Matheny said.

Saturday's key games to watch (all times ET)

Angels (Richards, 7-7) at Rangers (Holland, 10-9), 12:05 p.m. Preview >

Indians (Kazmir, 9-9) at Twins (De Vries, 0-1), 1:05 p.m. Preview >

Pirates (Morton, 7-4) at Reds (Arroyo, 14-11), 1:05 p.m. Preview >

Rays (Archer, 9-7) at Blue Jays (Happ, 4-7), 1:07 p.m. Preview >

A's (Parker, 12-7) at Mariners (Maurer, 4-8), 4:10 p.m. Preview >

Cubs (Jackson, 8-17) at Cardinals (Wainwright, 18-9), 4:15 p.m. Preview >

Red Sox (Lester, 15-8) at Orioles (Chen, 7-7), 7:05 p.m. Preview >

Tigers (Sanchez, 14-8) at Marlins (Eovaldi, 4-6), 7:10 p.m. Preview >

Phillies (Martin, 2-5) at Braves (Minor, 13-8), 7:10 p.m. Preview >

Rockies (Nicasio, 8-9) at Dodgers (Greinke, 15-3), 9:10 p.m. Preview >

If the postseason started today ...

AMERICAN LEAGUE
Wild Card: Indians at Rays
Division Series: Wild Card at Red Sox^ | Tigers^ at A's^

NATIONAL LEAGUE
Wild Card: Reds* at Pirates*
Division Series: Wild Card at Braves^ | Dodgers^ at Cardinals^

* - clinched postseason spot

^ - clinched division

Postseason 101

Magic numbers
To calculate a team's magic number, take the number of games it has remaining and add one. Then subtract the difference in the number of losses between that team and its closest pursuer.

Tiebreaker scenarios
A tiebreaker game will be played to determine a division winner, even if the tied clubs are assured of participating in the postseason. If a division championship tiebreaker is necessary, the head-to-head record between the clubs will determine home-field advantage. If the head-to-head record is tied, then division record will be the next tiebreaker. If the division record is tied, then intraleague record will be the next tiebreaker.

If two clubs are tied for the two Wild Card berths, home-field advantage will be determined by the head-to-head record between the clubs. If the head-to-head record is tied, then division record will be the next tiebreaker. If the division record is tied, then intraleague record will be the next tiebreaker.

Tiebreaker rules »

2013 postseason schedule

NL Wild Card Game: Tuesday
AL Wild Card Game: Wednesday
NL Division Series begin: Thursday
AL Division Series begin: Oct. 4
NL Championship Series begins: Oct. 11
AL Championship Series begins: Oct. 12
World Series begins: Oct. 23