© 2013 MLB Advanced Media, L.P. All rights reserved.

9/2/2013 9:16 P.M. ET

Showdown series begins with A's on their game

OAKLAND -- Whoever is wearing the proverbial target on their backs may be up for debate, but there's no denying that the A's and Rangers are the two contenders for American League West crown.

"Everything goes through Oakland," Rangers manager Ron Washington said before Monday's series opener between the two teams, to which Oakland skipper Bob Melvin replied, "I'll flip it back."

This much is clear: The Rangers hold a one-game lead over the A's one day into the final month of the season with two three-game series left between the two teams, with the first starting Monday at the Coliseum.

The A's are playing what Melvin called "the best we have in the second half to this point," after a three-game sweep of the Rays at home to grab a 2 1/2-game lead over Tampa Bay for the first Wild Card spot in the American League after a 3-1 series win over the AL Central-leading Tigers in Detroit.

The hot streak comes after a homestand in which the A's went 4-6 against the Astros, Indians and Mariners -- two of whom have losing records -- before it ended on Aug. 21.

"Everything that we did today is what's wrong with us," Melvin said after the final game of the homestand, a 5-3 loss to the Mariners.

Yet since then they've turned things around and are in a position for their second straight division title.

"I think our focus is a little better. Sometimes that goes on and off over the course of a season," Melvin said. "And when I speak like that I talk about us, everybody. Myself included. There are times during the season when you need to address some things and kind of re-energize the focus. That's just how I felt on that day, and the guys have been really consistent since I've been here about their effort level and so forth.

"We didn't have a good homestand and I was a little frustrated. But they played great baseball since."

The A's trailed the Rangers 8-5 in the season series and were 2-4 in Oakland. Yet the A's are batting .273 with 121 runs scored over the last 24 games after hitting .209 with 72 runs scored over the previous 23 contests -- an encouraging sign for sure as they play the last portion of the season.

"We can't really ever get too far ahead of ourselves here," Josh Donaldson said after Sunday's 5-1 win over the Rays. "Just last week people were starting to right us off and now they're jumping back on. Hopefully we can just continue to play good, clean baseball and continue our production."

Crisp homers in fifth, exits injured after sixth

OAKLAND -- A's outfielder Coco Crisp took a foul ball off his right leg in the sixth inning of Monday's 4-2 win over the Rangers, leading to his departure.

Crisp, who said he was "fine" after the game without elaborating, has been deemed day to day with a shin contusion.

Crisp was visited by manager Bob Melvin and a team trainer after fouling an 0-2 pitch from righty reliever Nick Tepesch off his leg. He stayed in the game, striking out one pitch later, only to exit it before the seventh began.

Chris Young, who started the game in right field, moved to center in Crisp's stead, and is expected to assume those duties should Crisp miss any more time. Brandon Moss entered the game in right field.

Crisp hit his career-high 17th home run in the fifth inning, marking the third straight day he's hit one out. He has seven home runs in his last 12 games.

All signs point to Norris returning on Thursday

OAKLAND -- All signs point toward Derek Norris returning to the A's from the 15-day disabled list upon his eligibility to do so on Thursday.

The A's backstop went 3-for-5 with a home run, three RBIs and two runs scored on Sunday in his second of three rehab starts with Triple-A Sacramento since fracturing his left big toe two weeks ago. He'll catch nine innings on Monday in the last game of the Minor League season and rest up as the 15 days run out.

"If he continues to be healthy, which we expect, then we'll activate him," A's manager Bob Melvin said.

Prior to joining the River Cats, Norris said the only baseball activity that caused him trouble was running at full speed, while running, cutting, swinging and squatting were fine.

The pain is manageable, he said, crediting his high tolerance for pain.

"It depends on where the break is," Melvin said. "He's obviously able to handle it right now. As far as his pain tolerance, I'm not really sure on that. If he says that, I believe him. Most catchers are."

With rosters having expanded, Norris' return will make him the fourth catcher on the roster with recent acquisition Kurt Suzuki, Stephen Vogt and John Jaso, who is on the DL with a concussion.

"I really don't' know yet," Melvin said about any pending roster moves. "Like most things we do, we try to match up the best on a particular day."

Top prospect Choice makes MLB debut as DH

OAKLAND -- It first appeared that Michael Choice's callup to the Major Leagues was a reward for a productive season in Triple-A, but he received the opportunity to prove himself right away.

One day removed from joining the big league club for the first time in his career, Choice batted ninth as the A's designated hitter in Monday's series opener against the Rangers -- the team the Arlington native rooted for growing up.

He didn't disappoint. Choice, the 10th overall pick in the 2010 First-Year Player Draft and the A's second-best prospect as rated by MLB.com, drew a walk in his first plate appearance in the third inning and reached base on an error in the fifth.

"First at-bat walk, which for the A's is like a starting out with a homer," A's manager Bob Melvin said.

In the fifth, Choice hit a sharp ground ball to Gold Glove third baseman Adrian Beltre, who made a throwing error that allowed Choice to hustle to first base. Coco Crisp hit the go-ahead home run one batter later to give the A's the 4-2 win.

"Obviously, he's an All-Star third baseman over there, and he doesn't make throwing errors at all," Crisp said. "So maybe because he was hustling down there he kind of shocked him with his size. He has some good speed. That was big for us hustling down there like that."

Choice batted a career-high .302 with 14 home runs and a career-high 89 RBIs in 132 games with the Triple-A River Cats this season and also had career highs in runs (90) and on-base percentage (.390).

"He's done everything well," Melvin said before the game. "He's had a great year. He's driven in runs, he's hitting for a high average, he's been consistent the whole year. ... Not only is this kind of a reward for him to bring him to the big leagues, but it's also that we obviously feel like he's somebody we can use."

Melvin alerted Choice that he would play the day prior, though he was nearly inserted into the game in numerous situations in Sunday's 5-1 over the Rays, Melvin said.

The skipper added that starting Choice off in the DH role should help him ease into Major League situations, though he credited his ability to play all three outfield positions. Crisp left the game early with a right shin contusion. Chris Young is Melvin's second option at center field, but Choice could receive time as a corner outfielder against left-handed pitchers.

"It depends on his performance," Melvin said. "We try to run out the best lineup on a particular day. Here recently, we've always had at least one left-handed hitter in the lineup. His performance will dictate how many at-bats he gets."

Choice's debut comes 28 years to the day that Jose Canseco played his first big league game in 1985. Choice's parents, wife, sister-in-law and son, Blair, were in attendance at the Coliseum.

Jeff Kirshman is an associate reporter for MLB.com. Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.