PITTSBURGH -- The Pirates missed another chance to right their ship on Thursday, turning a three-run lead over the Brewers into a 9-7 defeat. This latest loss not only moved them 5 1/2 games behind the Cardinals for the second National League Wild Card spot, but also dropped their record below .500 (74-75) for the first time since late May.

After losing their sixth straight home game, the Bucs begin their final road trip of the season in an opportunistic spot, taking on the Astros in the Friday night opener of a weekend series. The last time the Pirates won three straight, it came in Minute Maid Park on July 26-28.

After three games in Houston, Pittsburgh will conclude its road schedule with four games in Citi Field against the Mets. A.J. Burnett is scheduled to start Sunday's game against the Astros, thus the former Yankees right-hander would not get to go in one of those New York games.

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

Cardinals (Carpenter, 0-0) at Cubs (Volstad, 3-10), 2:20 p.m. Preview >

Braves (Hanson, 12-8) at Phillies (Kendrick, 9-11), 7:05 p.m. Preview >

Brewers (Marcum, 5-4) at Nationals (Jackson, 9-10), 7:05 p.m. Preview >

Dodgers (Blanton, 1-4) at Reds (Arroyo, 12-8), 7:10 p.m. Preview >

Pirates (Locke, 0-1) at Astros (Gonzalez, 2-1), 8:05 p.m. Preview >

If the postseason started today ...

This is how the teams would match up: 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