One win is all the Texas Rangers need to clinch a third consecutive AL West title.
A victory for the Oakland Athletics would secure their return to the postseason, but they're still looking to catch the Rangers.
Texas will try to hold off the hard-charging A's on Monday night when they meet in the opener of a three-game series that will determine the playoff fate of both teams.
The Rangers (93-66) own the best record in the AL and are headed to the postseason, but they're just two games ahead of the A's (91-68) in the West.
Winning just once during this three-game set at Oakland would clinch Texas' franchise-record third division crown. However, the A's are also eying a West title, despite being three games ahead of Los Angeles and Tampa Bay for the AL's second wild-card spot.
The Angels are visiting Seattle for three games, while Tampa Bay hosts postseason-bound Baltimore, which is tied atop the AL East with the New York Yankees.
''It's our choice,'' closer Grant Balfour said. ''If we go out there and win, good things are going to happen. The way we're playing right now I feel like we've got some good momentum going. We want to keep it rolling all the way through October.''
Rangers manager Ron Washington is wary of Oakland, which enters this series having won six of eight following a 5-2 victory over Seattle on Sunday to complete a three-game sweep.
"They're playing pretty good baseball," Washington told the team's official website. "They're playing their best baseball down the stretch, and they're finding ways to win."
The A's split a four-game set at Texas last week, and one of those victories came with Jarrod Parker (12-8, 3.44 ERA) on the mound.
The rookie right-hander allowed three runs and five hits in six innings of Wednesday's 9-3 win over the Rangers, improving to 3-0 with a 2.25 ERA in his last four starts.
Parker was outstanding in his only other meeting with Texas on June 4, carrying a no-hitter into the eighth before yielding one and leaving after the inning in a 12-1 home victory.
While Parker goes for his longest winning streak of the season, the Rangers are hoping Martin Perez (1-3, 5.03) can get his first victory since beating Oakland on June 30. The left-hander allowed two runs with five strikeouts over 5 1-3 innings in that game, but he's 0-3 with a 5.94 ERA in four starts since.
Perez would surely like to forget his latest outing which came opposite Parker on Wednesday. He was chased after two outs in the opening inning, surrendering five runs and six hits.
With their starter struggling, the Rangers may need another big offensive display after collecting 12 hits - three of them homers - in an 8-7 win over the Angeles to clinch a playoff berth in the nightcap of Sunday's doubleheader. Mike Napoli had a career high-tying six RBIs and a pair of home runs to help Texas rebound from a 5-4 loss in the opener.
Rangers third baseman Adrian Beltre said he's fine and should play this game after aggravating a strained left shoulder while leaping for a ball with his arm fully extended Sunday.
Beltre is hitting .444 with two homers and six RBIs in the last seven games, and that includes going 8 for 17 in four meetings with the A's. However, he's 4 for 26 in six games at Oakland, and 1 for 6 versus Parker.
Josh Hamilton is 0 for 5 with four strikeouts against Parker, but is 6 for 18 with three doubles in four games since last facing him.