The battle for the wild card spots in the Chase for the Sprint Cup title is getting more intense with the regular season fast approaching its conclusion.

With four races remaining before the Chase cut-off, seven drivers are duking it out for the two wild card positions in the playoffs. Marcos Ambrose added his name in the mix after winning last Sunday's road-course event in Watkins Glen, N.Y.

Kasey Kahne currently holds the top spot in the wild card rankings by virtue of his two wins this season. Ryan Newman finished 11th at Watkins Glen and moved up to the second wild card position, while Jeff Gordon fell from second to fourth after his 21st-place run there. Kyle Busch is third in the rankings. Ambrose is fifth and Joey Logano sixth.

Newman, Busch, Gordon, Ambrose and Logano have one victory each. All of those drivers are presently outside the top-10 in points.

Carl Edwards ranks seventh in the wild card contest, even though he sits 12th in the point standings. Edwards has not won in Sprint Cup since March 2011 (55 races ago). A win at Michigan would elevate him to the second wild card spot.

After the conclusion of the Sept. 8 race at Richmond, the 12-member field for the Chase will be decided, with the top-10 drivers in points and the wild cards making the show. The wild cards will go to the drivers outside the top-10 with the most wins, as long as they are ranked in the top-20. If multiple competitors outside the top-10 tie for victories, the tie-breaker will go to the race winner with the highest point standings position.

Heading into Michigan, the separation between 10th-place Denny Hamlin and 11th-place Kahne is 40 points. Hamlin is in pretty good shape to make the Chase, since he has two victories. He fell two spots in the standings after his 34th-place finish due to engine failure.

Busch, who is Hamlin's teammate at Joe Gibbs Racing, was on his way to a victory at Watkins Glen and therefore would have joined Kahne as those wild card contenders with two wins, but Busch unfortunately spun out while leading on the final lap, thanks to oil on the track and a bump from behind by second- place runner Brad Keselowski. He ended up finishing seventh.

"I thought that maybe (the next win) was going to be last weekend, but that wasn't meant to be," Busch said. "We still have some good tracks coming up. Hopefully, we can get our (car) to victory lane this weekend. If we do that, we'll have that second win for the wild card, and we'll go on into the last three races and see if we can't either keep ourselves in front of the 24 (Gordon) and the 39 (Newman) in points, in case one of them does get another win, or maybe even get ourselves another win."

Busch won at Michigan one year ago but finished 32nd there in June.

"For me, coming to Michigan, I tend to run well there," he said. "For whatever reason, I haven't had too many great finishes to show for it until last year, and then we had a great year there and got our first win last August."

Kahne and Busch have one victory each at Michigan, while Newman, Gordon and Edwards have two wins there apiece.

"We're just focused on doing the best we possibly can each week," Newman said. "We want to win. That's our goal this weekend. We have the wild card right now, but that can change after the first lap. So I'm just staying focused on being the best driver I can be and doing what we have to do to get to victory lane. Performance will take care of itself if we perform, especially if we outperform the wild card contenders."

After the Aug. 2011 race, the two-mile Michigan track received a new coat of asphalt, which led to record speeds when the series competed there two months ago. Ambrose not only claimed his first career Sprint Cup pole but also became the fastest driver in NASCAR qualifications in a quarter of a century. Ambrose's qualifying lap around the newly repaved track was clocked at 203.241 mph. He became the fourth different driver in NASCAR history to win a pole with a lap more than 200 mph. Bill Elliott had last done it in July 1987 at Talladega.

The new track surface created major issues with the tires used for this year's spring race at Michigan. After several teams experienced tire blistering during Thursday and Friday's practice sessions, NASCAR and Goodyear made the decision to use a tougher left-side tire for the race. The higher than expected speeds in practice at Michigan caused significantly higher left-side tire temperatures and therefore blistering.

An additional Sprint Cup practice session was held the evening before the race, allowing teams to familiarize themselves with the new tires and make further adjustments to their race setups.

Dale Earnhardt Jr. went on to take the checkered flag at Michigan, snapping a four-year, 143-race winless streak in Sprint Cup.

Several weeks ago, 28 Sprint Cup teams participated in a tire test at Michigan. Goodyear has selected a new combination for this Sunday's race. It will be a combination of the original tires from the April test and a slightly softer version of the harder tires used during the June event.

"That (July 30) test didn't go spectacularly well for us, but we knew it was just more of a test to try and learn things," said Gordon, who started 28th and finished sixth at Michigan earlier this year.

Forty-five teams are on the preliminary entry list for the Pure Michigan 400.

Series: NASCAR Sprint Cup. Date: Sunday, August 19. Race: Pure Michigan 400. Site: Michigan International Speedway. Track: two-mile oval. Start time: 1 p.m.(ET). Laps: 200. Miles: 400. 2011 Winner: Kyle Busch. Television: ESPN. Radio: Motor Racing Network (MRN)/SIRIUS NASCAR Radio.