The dog days of Summer are rapidly approaching as the 2011 Major League regular season has hit the 70 game mark. The two preseason favorites; Boston in the American League and Philadelphia in the National League currently sit at the top of their division, but there are a couple of surprise teams leading or contending in theirs.

The following is a look at each division leader along with their updated mlb odds to win the league pennant and the World Series as provided by

Boston stumbled out of the gate this season, but that is just a distant memory to a team that continues to roll right along with 13 wins in its last 15 games. The Red Sox are an AL-best 43-28, but still only have a 1.5 game lead over New York and a 4.5 game lead over Tampa Bay in the AL East. They are currently listed at 3/2 to win the American League and 13/4 to win the World Series after being listed at 11/4 and 6/1 respectfully in early May.

Cleveland currently holds a precarious one-game lead over Detroit in the AL Central, but the bloom is off the rose for baseball’s biggest surprise team this season. The Indians are 39-31 overall but just 5-5 in their last 10 and 7-11 in the month of June. They were listed at 10/1 to win the pennant in May, but have fallen back to 16/1 in the latest odds. Their odds to win the World Series have gone from 20/1 to 30/1.

The AL West remains wide open as just five games separate the last-place Oakland Athletics from the first-place Texas Rangers. Texas holds the lead over Seattle by just a half a game after losing seven of its last 10. It is 38-35 overall and 18-22 on the road. Last year’s AL Champions are currently listed at 6/1 to repeat after starting the season at 8/1. Texas’s odds to win the World Series started at 18/1 but have improved to 13/1.

Philadelphia’s dominant starting rotation has lived up to its potential so far as it has the Phillies in first-place in the NL East with a MLB-best record of 45-28. They have won eight of their last 10 and have opened a five-game lead over Atlanta in the division. They began the season as the odds-on-favorite to win both the NL Pennant and the World Series and things have not changed. Philadelphia remains a prohibitive 13/10 favorite to return to the World Series and a 3/1 favorite to win it.

The NL Central is shaping up as a four team race with the surprising Pittsburgh Pirates just four games in back of Milwaukee and St. Louis for the lead with last year’s champs, Cincinnati sandwiched in between. The Brewers (40-33) have the best odds of the bunch to win the NL at 7/1 and the World Series at 14/1. The Cardinals (40-33) are 8/1 and 16/1 while the Reds (38-35) are 11/1 and 22/1. The flyer of the group is the upstart Pirates (35-36) at 40/1 to win the NL and 100/1 to win the World Series.

The NL West is another tight division with the defending World Champion San Francisco Giants currently in front at 39-33. They have a half game lead over Arizona and a 3.5 game lead over Colorado. The Giants have gone 12-12 since losing their All-Star catcher Buster Posey for the season with a broken ankle. Despite the loss, the odds makers are still fairly bullish on this team’s chances to repeat as it has gone from being a 7/1 favorite to win the NL to 15/2 and from 14/1 to win the World Series to 15/1.