Postseason hopes are flying all over the Major League map as September's middle weekend plays out, and Friday's opening act sent thrills soaring deep into the night.

The home run was on center stage with Chris Davis crushing No. 50 north of the border to help the Orioles' cause in the crowded American League Wild Card race. That wasn't all for the long ball, as back-to-back-to-back homers actually weren't enough in Pittsburgh and a dagger of a grand slam in Boston brought the Red Sox a little closer to the AL East title.

For Davis, the fact that his homer pushed the Orioles to a key victory in the heat of a playoff chase was bigger than any milestone.

"I've said it all along, it's nice to have personal goals and to reach your own goals, but when the team is winning, that's what makes it that much sweeter," Davis said.

Homers were only part of the story as the Pulse of the Postseason picked up steam, making it clear this will be a weekend to remember.

After Friday's action, there are six teams within 4 1/2 games for the two AL Wild Card spots, and suddenly the race for the second NL Wild Card is a little bit tighter, with the red-hot Nationals pulling to within 4 1/2 games of the cooling Reds.

Starting with a day game on the South Side, the Indians got in the first salvo for a contender Friday, using a little bit of offense and a whole lot of pitchers -- eight of them -- to take a 3-1 victory at U.S. Cellular Field over the White Sox.

As evening games began, the Rays found the scoreboard in the fourth inning at Target Field, scoring a pair of runs for a lead that looked safe in the hands of starter Chris Archer -- and it was. The Rays would close out the Twins, 3-0, with Fernando Rodney shooting his save arrow in support of Archer's ninth win.

The rest of the AL Wild Card race was, well, wild. The Tigers finished off the Royals for a 6-3 win, but the rest of the games had excitement into the late innings.

At the time the Rays pulled ahead in Minnesota, Davis stepped to the plate in Toronto with the teams tied in the eighth inning. He went opposite field for his 50th, giving the O's the lead en route to a 5-3 victory over the Jays. As the Orioles tweeted at the time, "Ladies and gentlemen, Chris Davis has hit 50 home runs! #Crush50"

And around the same time as Davis' milestone homer, the Yankees put a couple guys on base and knocked Red Sox starter John Lackey out of the game in the seventh. That sequence turned into a bases-loaded double by Robinson Cano that tied the game at 4.

But it didn't take long for the Red Sox to rally, as Jarrod Saltalamacchia deposited a grand slam to right-center field in the bottom half for an 8-4 Boston win. As MLB tweeted, "The @RedSox are 1st to 90 wins. #Round Numbers"

That left the Rangers as the only Wild Card contender still in action, and they faced a seven-run deficit against the A's, kick-started by Yoenis Cespedes' three-run bomb in the first. But a six-run rally in the eighth brought the Rangers to within a run -- before Alex Rios was called out at third base for the final out on a single hit to Cespedes in left. With a 9-8 victory, the A's moved to 4 1/2 games ahead of Texas while keeping that AL Wild Card race tight.

"This is what we've been working toward all season long, to be in the driver's seat in September and be able to control our own destiny," said A's reliever Sean Doolittle, who recorded a four-out save.

Meanwhile, the NL Central contenders went to work, and the Brewers' Kyle Lohse wrapped up his first complete game since 2011 to knock the Reds down a peg, 5-1. The Pirates and Cardinals made it a little more exciting.

At PNC Park, the thrills for the home team came in the fourth inning, when Pedro Alvarez hit a stand-up inside-the-park home run, which was followed by homers from Russell Martin and Garret Jones to erase a three-run deficit.

But the homer did the Pirates in, too. A two-run shot by the Cubs' Anthony Rizzo in the seventh inning proved to be the winner in a 5-4 Pittsburgh loss.

The Cardinals, meanwhile, scrambled like mad to catch up to the Mariners in the late innings. In the eighth, Pete Kozma stole third base just before a possible double-play ball that would have ended the threat. Instead Kozma scored as Jon Jay beat out the relay to first. Then, in the 10th, it was Kozma on third again, scoring when Seattle catcher Mike Zunino let one by for a passed ball -- yes, the walk-off passed ball for the 2-1 victory.

"I was just ready for anything," Kozma said. "You have to do anything you can to get home safely."

The Reds need to watch out for Washington, which has won seven straight and nine of 10, with Ryan Zimmerman hitting yet another homer -- his ninth in his last 11 games -- in a 6-1 win over the Phillies. The Nats conspired with the Padres to keep the Braves waiting for the NL East title, with San Diego taking a 4-3 win at Turner Field.

The night wrapped up with the Dodgers unable to rally in the ninth inning this time, dropping a 4-2 game to the Giants. Still, L.A. got a little closer to the NL West title when the D-backs lost to the Rockies, 7-5.

As the Pulse of the Postseason continues into Saturday, the excitement will be spread around all over the map once again.

The six teams currently vying for the American League Wild Card will be found in six different venues, five of them playing on the road. The trio of NL Central contenders are all presented with sub-.500 teams to play, and there are rivalries playing out from Massachusetts to Texas to California.

All eyes will be on Texas and Tampa Bay as they try to hold off the AL Wild Card pursuers for another day. The Rangers turn to ace Yu Darvish against the A's, and the Rays have 15-game winner Matt Moore on the mound.

Both teams have a sense of urgency as they head into Saturday's action, knowing four teams are breathing down their necks, wanting those precious postseason spots.

"We're not out of it, we've still got fight," Rangers manager Ron Washington said after Friday's loss. "We're going to come back [Saturday] and still fight and we're going to get it right. We never quit. We just didn't win the game."

In the NL Central, the Pirates and Cardinals are at home, while the Reds will play again on the road at Milwaukee. The Pirates and Cards each won two of three against the Brewers in the last couple of weeks, and the Reds will have to win both Saturday and Sunday to match that.

With rivalries renewed between the A's and Rangers, Yankees and Red Sox and Giants and Dodgers -- all with postseason implications -- another day of stretch-run excitement awaits.

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

Reds (Bailey, 10-10) at Brewers (Hellweg, 1-3), 1:05 p.m. Preview >
Winner of his last five decisions over eight games, Homer Bailey gets the ball in a game the Reds could really use.

Yankees (Sabathia, 13-12) at Red Sox (Lester, 13-8), 1:05 p.m. Preview >
The Red Sox are putting the pedal to the metal to get the division wrapped up.

A's (Colon, 15-6) at Rangers (Darvish, 12-8), 1:05 p.m. Preview >
After Friday's thriller, the A's could do some serious damage to the Rangers' division hopes with a win Saturday.

Orioles (Tillman, 16-5) at Blue Jays (Rogers, 5-7), 4:07 p.m. Preview >
The Orioles' Chris Tillman is looking to become the first 17-game winner for Baltimore since Mike Mussina in 1999.

Cubs (Baker, 0-0) at Pirates (Cole, 7-7), 7:05 p.m. Preview >
At least it's not Friday the 13th anymore. The Pirates have lost their last 11 on that freaky day now.

Phillies (Hamels, 7-13) at Nationals (Gonzalez, 10-6), 7:05 p.m. Preview >
Time is of the essence, but the Nationals have picked a good time to be the hottest team around.

Royals (Santana, 8-9) at Tigers (Fister, 12-8), 7:08 p.m. Preview >
The Tigers are 45-27 at home this season and have won 78 of the last 116 at Comerica Park.

Indians (Jimenez, 11-9) at White Sox (Rienzo, 2-1), 7:10 p.m. Preview >
The Tribe has the look of a team collecting itself on the road as the stretch run hits high gear.

Padres (Erlin, 2-2) at Braves (Medlen, 13-12), 7:10 p.m. Preview >
The Braves' Magic Number is stuck at six after Friday's loss and the Nationals' win.

Rays (Moore, 15-3) at Twins (Albers, 2-2), 7:10 p.m. Preview >
Pitching was the difference Friday night, and Moore steps in as the team's winningest pitcher.

Mariners (Paxton, 1-0) at Cardinals (Wacha, 3-0), 7:15 p.m. Preview >
The Cardinals found a way to win Friday, with a little help but a lot of making their own opportunities.

Rockies (Oswalt, 0-5) at D-backs (Miley, 9-10), 8:10 p.m. Preview >
The D-backs remain 12 1/2 out in the NL West and nine games out in the NL Wild Card.

Giants (Lincecum, 9-13) at Dodgers (Nolasco, 13-9), 9:10 p.m. Preview >
The magic number is down to four for the Dodgers, which means they still could clinch the NL West this weekend.

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