HOUSTON -- The Phillies' seven-game winning streak came to an end on Thursday at the hands of the last-place Astros. Philadelphia held a 4-0 lead after three innings, but a three-run homer in the fourth and a three-run rally in the eighth gave the Astros a 6-4 victory.

"We had a chance to win the game sitting there in front of us," Phillies manager Charlie Manuel said. "The bottom line is that we didn't add on runs and we didn't execute either."

The Cardinals beat the Dodgers, 2-1, on Thursday night, putting the Phillies four games behind St. Louis, which holds the second spot in the National League Wild Card race. The Pirates (three games back), Brewers (3 1/2 games back) and the D-backs (4 1/2 games back) were all off Thursday.

St. Louis continues its series in Los Angeles on Friday. Pittsburgh will start a three-game series with the Cubs at Wrigley Field, Milwaukee hosts the Mets for three games and the D-backs travel to San Francisco for three.

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

Pirates (McDonald, 12-7) at Cubs (Rusin, 0-2), 2:20 p.m. Preview >

Nationals (Detwiler, 9-6) at Braves (Medlen, 8-1), 7:35 p.m. Preview >

Phillies (Hamels, 14-6) at Astros (Gonzalez, 2-0), 8:05 p.m. Preview >

Mets (Niese, 10-9) at Brewers (Fiers, 9-7), 8:10 p.m. Preview >

Giants (Cain, 13-5) at D-backs (Skaggs, 1-1), 9:40 p.m. Preview >

Cardinals (Kelly, 5-6) at Dodgers (Capuano, 11-10), 10:10 p.m. Preview >

If the postseason started today ...

AMERICAN LEAGUE
Wild Card: Second Wild Card at First Wild Card
Division Series: Second-best AL record vs. Third-best AL record | Best AL record at Wild Card winner

NATIONAL LEAGUE
Wild Card: Second Wild Card at First Wild Card
Division Series: Second-best NL record vs. Third-best NL record | Best NL record at Wild Card winner

Postseason Bracket »

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 the 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 the division record will be the next tiebreaker.

Tiebreaker rules »

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