ARLINGTON -- The Rangers' hold on the American League West became a little more precarious on Saturday night.

The Rangers rallied from a six-run deficit to tie the Mariners, only to lose, 8-6. Oakland cruised to a 5-2 win over Baltimore, cutting Texas' lead to two games, the closest the division race has been since April 13.

The Rangers have been in first place since April 9, the fourth game of the season. But with seven of their 17 remaining games against the Athletics, the Rangers will have to beat the division rival head-to-head to win their third straight title.

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

Mariners (Beavan, 9-9) at Rangers (Harrison, 16-9), 3:05 p.m. Preview >

Orioles (Wolf, 5-10) at A's (Straily, 2-0), 4:05 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.

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