The playoff picture became a little clearer after Saturday's contests, especially in the National League.
The Reds were crowned NL Central champions in Cincinnati after a 6-0 win over the Dodgers. Mat Latos dominanted for eight innings and home runs from Jay Bruce and Brandon Phillips helped secure the victory.
Celebrating on the field and with a champagne shower afterwards, the Reds have now won two NL Central titles in the last three seasons.
"Celebrate, get it in, enjoy it, because this is just the beginning," Phillips said. "We're still on a mission. We've got things we've got to do and got to prove."
The loss moved the Dodgers three games back of the Cardinals for the second NL Wild Card spot, after St. Louis picked up a 5-4 win over the Cubs in 10 innings. The Brewers also took a step back, taking a 10-4 loss to the Nationals to fall 2 1/2 back of the Cardinals for that final spot.
The Giants joined the Reds as champs later in the night, beating the Padres, 8-4, for their sixth straight win to clinch the NL West. Madison Bumgarner pitched a solid 52/3 innings, while Marco Scutaro had three hits to help San Francisco to its second division title in the last three years.
"It never gets old," general manager Brian Sabean said after the game. "It's a special group. The long and windy road this season's been, I don't know that we're known for any real star quality. I can't remember a team that attacked the schedule at the end."
In the American League East, games were filled with drama in extra innings. After the Orioles got a 9-6 win over the Red Sox in 12 frames to put the pressure on the Yankees, New York got a thrilling 10-9 win over the A's in 14 innings to maintain its one-game lead over Baltimore in the division.
The Yankees rallied from a four-run deficit in the 13th inning before walking off an inning later, when Ichiro scored the winning run with the bases loaded on a ground ball that kicked away from A's first baseman Brandon Moss.
"When they scored four runs, a lot of fans went home," Ichiro said. "I bet they're shocked to get home and see the score."
That A's loss, coupled with a 4-2 Angels win over the White Sox, moved the Halos just 2 1/2 games back of Oakland for the second AL Wild Card spot.
It also made the race for the top spot in the AL Central that much tighter. With the White Sox taking a loss and the Tigers getting a 8-0 win over the Twins, behind Doug Fister's first career shutout and Miguel Cabrera's 42nd home run of the season, Detroit moved a 1/2 game back of Chicago for first place in the division.
Sunday's key games to watch (all times ET)
Game 1: Twins (Diamond, 11-8) at Tigers (Scherzer, 16-6), 1:05 p.m. Preview >
The Tigers can tie the White Sox atop the AL Central if they can get a win in game 1 of the double-header.
Game 2: Twins (Walters, 2-4) at Tigers (Smyly, 4-3), 7:05 p.m. Preview >
The Tigers are inching ever closer to the top of the AL Central. It's possible with two wins on Sunday that they could be in first place come the end of the day.
A's (Griffin, 6-1) at Yankees (Kuroda, 14-10), 1:05 p.m. Preview >
The A's will look to get back on track after two tough extra inning losses, while the Yankees look to create more breathing room between themselves and the Orioles.
Braves (Hudson, 15-6) at Phillies (Lee, 6-7), 1:35 p.m. Preview >
The Phillies will turn to their hottest pitcher, Cliff Lee, to get them back on track against the Braves, who have a six-game lead for the first NL Wild Card spot.
Brewers (Gallardo, 16-8) at Nationals (Wang, 2-3), 1:05 p.m. Preview >
Milwaukee is 2 1/2 games back of the Cards for the second NL Wild Card spot as ace Yovani Gallardo takes the hill for a much needed win.
Orioles (Tillman, 8-2) at Red Sox (Doubront, 11-9), 1:35 p.m. Preview >
The surging Orioles will look to complete a three-game sweep of the Red Sox on Sunday afternoon at Fenway Park.
Blue Jays (Jenkins, 0-1)) at Rays (Hellickson, 8-10), 1:40 p.m. Preview >
The Rays have a four-game winning streak going into Sunday's contest and are 3 1/2 games back of the A's for the second AL Wild Card spot.
Pirates (Burnett, 15-8) at Astros (Lyles, 4-11), 2:05 p.m. Preview >
The Pirates will look to add a much-needed victory on Sunday as they try and make up ground for the second spot in the NL Wild Card.
Cardinals (Lohse, 15-3) at Cubs (Germano, 2-8), 2:20 p.m. Preview >
St. Louis has won five of its last six games and currently holds a 2 1/2 game lead over the Brewers for the final NL playoff spot.
D-backs (Kennedy, 14-11) at Rockies (Francis, 5-6), 8:10 p.m. Preview >
Ian Kennedy takes the hill for the D-backs, who sit 4 1/2 games back of the Cards for the second NL Wild Card spot.
White Sox (Floyd, 10-10) at Angels (Weaver, 18-4), 3:35 p.m. Preview >
The Angels are 2 1/2 games back of the A's for the second spot in the AL Wild Card, while the White Sox hold just a 1/2 game lead over the Tigers in the AL Central.
Padres (Stults, 6-3) at Giants (Petit, 0-0), 4:05 p.m. Preview >
Riding high after clinching the NL West Saturday night, the Giants send Yusmeiro Petit to the hill for his first start since 2009.
Rangers (Dempster, 6-2) at Mariners (Vargas, 14-10), 4:10 p.m. Preview >
Even with a tough 1-0 loss to the Mariners on Saturday, the Rangers still hold a four-game lead over A's in the AL West.
Dodgers (Harang, 9-10) at Reds (Bailey, 12-9), 8:05 p.m. Preview >
Fresh off winning the NL Central crown, the Reds will send Homer Bailey to the hill.
If the postseason started today ...
Wild Card: Orioles at A's
Division Series: Yankees vs. White Sox | Rangers vs. Wild Card winner
Wild Card: Cardinals at Braves
Division Series: Reds vs. Giants | Nationals at Wild Card winner
For the 2012 postseason, the team with the better record will play the first two games on the road to start the Division Series.
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.
A tiebreaker games 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 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.
2012 postseason schedule
Wild Card playoff games: Oct. 5
Division Series: Oct. 6-12
AL Championship Series: Oct. 13-21
NL Championship Series: Oct. 14-22
World Series: Oct. 24-Nov. 1
Quinn Roberts is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.