General managers on contending teams are clamoring to find additions to their rosters before Monday's trade deadline. A starting pitcher, a set-up man or an extra bat can be crucial in the pennant chase.

But before making the decision to upgrade, which teams are really in the race? According to oddsmakers, it looks like a six-team contest to win the World Series, as the Los Angeles Dodgers, Houston Astros, Boston Red Sox, Chicago Cubs, Washington Nationals and Cleveland Indians have separated themselves from the rest of the pack.

The Dodgers, who are on pace to win 100 games, have the best odds at 11/4. Los Angeles has the best earned-run average (3.12) in the majors and is fifth in runs (524). It's unclear if team president Andrew Freidman will pull the trigger on a deal to bolster the starting rotation or add a left-handed reliever. Walker Buehler, rated by Baseball America as the No. 2 best pitching prospect, would likely be part of a possible deal to land Texas Rangers' star Yu Darvish. However, it wouldn't be surprising if the Dodgers' front office held off on making a big splash before July 31.

The Astros have the second-best odds at 9/2 odds. Houston boasts the best offense in baseball (599 runs) and well ahead of the Washington Nationals, who are No. 2 at 563 runs. There have been questions as to how well Houston's pitching can perform with the return of Dallas Keuchel and Collin McHugh from injuries. However, general manager Jeff Luhnow is not expected to concede top prospects to land a difference maker.

After the Dodgers and the Astros, the Red Sox, Cubs and Nationals each have 7/1 odds.

The Red Sox have a slim half-game lead on the New York Yankees and are just three games up on the Tampa Bay Rays. Boston has the third-best ERA (3.69) but there has been speculation that general manager Dave Dombrowski will pursue rotation help with David Price being placed on the disabled list with an ailing elbow. However, he recently stated that there is no interest in a "big deal" for a starting pitcher.

The Cubs, in a tight race in the NL Central, are the only team to truly make a serious move before the deadline, acquiring starting pitcher Jose Quintana for top prospects. Quintana has produced in two starts, allowing just three earned runs over 13 innings. But the rest of the starting rotation might be viewed as an enigma. Jon Lester, Jake Arrieta and John Lackey have all seen a significant dip in their ERA from last season's World Series year, prompting questions over whether Theo Epstein should consider another deal for a starter.

Unlike the Cubs and Red Sox, the Nationals have their division basically wrapped up. Tanner Roark is coming off back-to-back solid starts and Stephen Strasburg is only expected to miss one start, but reports have still linked the Nats to Darvish and Oakland A's star Sonny Gray to strengthen one of the most efficient rotations in baseball. The bullpen, on the other hand, is probably in need of a boost with no true closer. Relievers Ryan Madson and Sean Doolittle were an upgrade, but general manager Mike Rizzo may consider one more deal and he has plenty of prospects to offer.

The Indians, with a slim two-game lead on the Kansas City Royals, are not far behind the pack at 15/2. Cleveland boasts a 3.70 ERA but president of baseball operations Chris Antonetti recently said that the team is "definitely going to be active at the deadline," with the needs being a pitcher and strengthening the bench. The Indians have been linked to Jay Bruce, but recent reports suggest that New York Mets haven't received much interest in the power-hitting right-fielder.

There are still plenty of other teams in the mix. The New York Yankees have 10/1 odds. The Arizona Diamondbacks (20/1 )and Colorado Rockies (25/1) have clear paths to the two wild-cards spots. The Royals (33/1) and Milwaukee Brewers (40/1) are not far out of their division races.

MLB World Series Odds (VegasInsider.com)

Los Angeles Dodgers 11/4

Houston Astros 9/2

Boston Red Sox 7/1

Chicago Cubs 7/1

Washington Nationals 7/1

Cleveland Indians 15/2

New York Yankees 10/1

Arizona Diamondbacks 20/1

Colorado Rockies 25/1

Kansas City Royals 33/1

Tampa Bay Rays 36/1

Milwaukee Brewers 40/1

Minnesota Twins 66/1

Pittsburgh Pirates 66/1

St. Louis Cardinals 66/1

Texas Rangers 66/1

Seattle Mariners 80/1

Baltimore Orioles 100/1

Detroit Tigers 100/1

Los Angeles Angels 100/1

New York Mets 100/1

Toronto Blue Jays 100/1

Atlanta Braves 150/1

Miami Marlins 250/1

Oakland Athletics 500/1

San Francisco Giants 500/1

Cincinnati Reds 1000/1

Chicago White Sox 3000/1

Philadelphia Phillies 5000/1

San Diego Padres 5000/1

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