Heading into a new week of September in Major League Baseball, some scenarios for the next, most important month -- you know, the one with postseason games -- are beginning to crystallize.

We know, for example, that the Dodgers, Braves, Red Sox (with or without injured Jacoby Ellsbury ) and Tigers are looking great for postseason berths, barring historic collapses over the last three weeks of the regular 162-game slate.

We also know that the National League Central has three teams within 1 1/2 games of the division lead. The Cardinals lead the Pirates and the Reds, who are in a virtual tie for second, and that one will shake out the way it shakes out. It's impossible to predict at this point.

But the Pulse of the Postseason for Sunday was more about teams stepping up to produce important results when desperation might have just started creeping in a bit.

The Rangers, Rays and Yankees all needed victories in the worst way, and they all got them in the best way.

Take the Rays, who are in line for the second Wild Card spot in the American League right now but were in the midst of a 3-6 record on a West Coast road trip and weren't hitting the ball. Through seven innings against the Mariners, they were trailing, 1-0. Then they broke through with three runs in the eighth and another in the ninth to win, 4-1.

"It just typifies this entire West coast thing," Rays manager Joe Maddon said. "I know the rotation of the Earth is the same. The sunrise and the sunset, I get all of that. But we have just not played normal Rays baseball out here."

Later, with his club's two-game cushion in the Wild Card race intact, Maddon was able to wax a bit cyber-philosophically, as did his players:

Meanwhile, the Rangers needed a win badly. They were on a three-game losing streak against an Angels team with nothing to lose late in the season, and the AL West-leading A's were up big on Houston. Texas needed to rally, and it did.

A seventh-inning rally capped by an RBI double by Alex Rios gave them a 4-3 win and allowed them to stay 1 1/2 games behind Oakland. They headed home to face the Pirates with smiles on their faces and maybe a bit of momentum, too.

In the Bronx, the Yankees were reeling from seemingly endless beatdowns at the hands of the visiting first-place Red Sox, and their Wild Card hopes weren't exactly brimming.

Then again, when Ichiro Suzuki is able to scamper home on a wild pitch to win, 4-3, and the Yankees can visit Baltimore only a half-game behind the Orioles and only 2 1/2 games out of the Wild Card mix, things suddenly look brighter in the Bronx.

"Obviously, if we lose this one today, it would have been a big hit mentally," Ichiro said through an interpreter. "It would have been tough, to be honest. But we did win, and hopefully we can take this win here, get on a run, and really use it to our advantage."

And isn't that the mantra of every team right about now?

Take the NL Central, which gets nuttier by the day, and those ridiculous Reds. While the division-leading Cardinals were beating the Pirates to keep their lead, the Reds were walking off against the Dodgers to pull into a virtual tie for second with Pittsburgh.

It didn't hurt that a certain Cincinnati slugger had himself quite a game, too. That would be Jay Bruce, who hit two homers off Clayton Kershaw.

Elsewhere around the pumping Pulse of the Postseason, we saw division leaders with comfy leads losing again. Atlanta, Detroit and Los Angeles all lost Sunday, although they're still looking good for October.

The A's kept on winning and seem to be in the right frame of mind as they move forward, even with Texas still not going away.

"There's a combination of some good things happening right now," Oakland manager Bob Melvin said. "It just seems like this is a very good stretch for us when you think back to our body of work throughout the whole season."

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

Royals (Santana) at Indians (Jimenez, 10-9), 7:05 p.m. Preview >
The matchup of Wild Card fringe contenders takes an intriguing turn here with this pitching matchup. It's hard to know which Jimenez will show up, but Cleveland's hoping for the unhittable one.

Yankees (Sabathia, 13-11) at Orioles (Tillman, 15-5), 7:05 p.m. Preview >
Two AL East rivals playing for their Wild Card lives, with two of their best starters toeing the slab. That's must-watch ball.

Braves (Medlen, 12-12) at Marlins (Alvarez, 3-3), 7:10 p.m. Preview >
The Braves have lost four in a row. It's hardly time to panic, but they could use a win here to get the good vibes going again.

Cubs (Wood, 8-11) at Reds (Arroyo, 13-10), 7:10 p.m. Preview >
The Reds are hot and can't let down. Arroyo has been terrific all season and has playoff experience that should come in handy in a big game like this.

Nationals (Gonzalez, 9-6) at Mets (Torres, 3-3), 7:10 p.m. Preview >
Washington could use the Gio Gonzalez that almost won the Cy Young Award last year. They're running out of games.

Pirates (Cole, 6-7) at Rangers (Darvish, 12-7), 8:05 p.m. Preview >
Cole steps up to a big-league pennant race here and faces a brilliant opponent in Darvish. The Pirates are still looking to cement their first winning season in 21 years.

Tigers (Scherzer, 19-2) at White Sox (Sale, 10-12), 8:10 p.m. Preview >
The pitching matchup of the night has Scherzer gunning for 20 wins and Sale gunning for a .500 record in a season in which his statistics indicate he should be far better than that.

D-backs (Delgago, 4-5) at Dodgers (Nolasco, 12-9), 10:10 p.m. Preview >
Delgado has been good of late, but Nolasco has been better. Arizona can make a huge statement in this series or fall further out of it fast.

If the postseason started today ...

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

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

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 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.

Tiebreaker rules »

2013 postseason schedule
NL Wild Card Game: Oct. 1
AL Wild Card Game: Oct. 2
NL Division Series begin: Oct. 3
AL Division Series begin: Oct. 4
NL Championship Series begins: Oct. 11
AL Championship Series begins: Oct. 12
World Series begins: Oct. 23