West is 1: Rangers win, Gray blanks Astros

Mets, Blue Jays increase division leads with dramatic victories

West is 1: Rangers win, Gray blanks Astros

The race for the American League West is heating up with just four weeks remaining until the start of the postseason.

But that's not the only division worth following over the final month of the regular season. Here's a look at some key developments from Tuesday's action that helped shape the playoff picture:

Rangers tighten gap with Astros
The Astros were shut out by the A's, 4-0, and saw their lead in the AL West shrink to one game over the second-place Rangers, who outslugged the Mariners, 9-6.

Gallo's no-doubter

It's the closest the Rangers have been to first place in the division since they were one game back on April 18.

Texas has quietly been moving up the standings for over a month thanks to a 23-12 record since Aug. 1, which is the second-best mark in the AL during that span (the Blue Jays are 26-8).

Venable on Rangers' big win

Mets rally again over Nationals
For the second straight day, the Mets pulled off a comeback win over the Nationals in a critical three-game series in Washington D.C. The Mets now lead the second-place Nats by six games in the National League East.

With the Nationals holding a 7-1 lead entering the seventh inning, the Mets rallied for six runs against three relievers to tie the game. In the eighth, Kirk Nieuwenhuis belted a go-ahead homer and the Mets held on to win, 8-7.

Nieuwenhuis' go-ahead home run

The late-inning heroics overcame a rough start from Mets ace Matt Harvey, who allowed a career-high seven earned runs over 5 1/3 innings.

"That was so much fun to watch," Harvey said. "I was frustrated with my own performance, but overall we won the game. And that's huge."

Blue Jays get some breathing room
The Blue Jays scored four runs in the 10th inning to outlast the Red Sox, 5-1, and reclaim a 1 1/2-game lead in the AL East over the second-place Yankees, who fell to the Orioles, 2-1.

Blue Jays score four in 10th

Tuesday's results guarantee the Blue Jays will hold a division lead entering a pivotal four-game series against the Yankees that begins on Thursday at Yankee Stadium.

The Yankees, meanwhile, are holding onto a four-game lead over the Rangers for the AL's top Wild Card.

Other things to know
• The Royals dropped their magic number to clinch the AL Central to 13, thanks to a 4-2 win over the second-place Twins at Kauffman Stadium.

The Twins are 2 1/2 games behind the Rangers for the second Wild Card.

• The Pirates beat the Reds, 7-3, to move within 4 1/2 games of the NL Central-leading Cardinals, who lost to the third-place Cubs, 8-5.

The Pirates own a two-game lead for the top NL Wild Card over the Cubs.

• The Cardinals saw their magic number to clinch a postseason berth reduced to nine, by virtue of the Nationals' loss to the Mets. The Cards could clinch a playoff spot as early as Sunday, and would be the first team to do so.

• The Dodgers won their second straight game over the Angels to maintain an 8 1/2-game lead in the NL West over the second-place Giants, who beat the D-backs, 6-2.

Meanwhile, the loss dropped the Angels 4 1/2 games behind the Rangers for the second AL Wild Card.

If the postseason began today ...

AMERICAN LEAGUE
Wild Card: Rangers at Yankees
Division Series: Wild Card at Royals, Astros at Blue Jays

NATIONAL LEAGUE
Wild Card: Cubs at Pirates
Division Series: Wild Card at Cardinals, Mets at Dodgers

2015 POSTSEASON SCHEDULE
AL Wild Card Game: Oct. 6
NL Wild Card Game: Oct. 7
AL Division Series begin: Oct. 8
NL Division Series begin: Oct. 9
NL Championship Series begin: Oct. 16
AL Championship Series begin: Oct. 17
World Series begins: Oct. 27

Austin Laymance is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.