World Series odds: Cubs now 12-1

After agreeing to a six-year, $155 million deal with Jon Lester late Tuesday night, the Chicago Cubs, at 12-1, have moved into the top tier of favorites in Las Vegas to win the 2015 World Series.

The Cubs began the offseason at 40-1 to win the World Series at the Westgate SuperBook but have seen their odds steadily improve over the past month with the addition of manager Joe Maddon. They were at 18-1 to begin the week at the SuperBook, before inking Lester.

At 12-1, the Cubs are now among the top seven teams in the SuperBook's World Series odds. The Los Angeles Dodgers and Washington Nationals are co-favorites at 7-1, followed by the Los Angeles Angels at 8-1 and the Detroit Tigers at 10-1.

The St. Louis Cardinals, Baltimore Orioles and Cubs are all 12-1.

The Cubs, who haven't won the World Series since 1908, always receive plenty of attention from bettors in Las Vegas. That's again the case this season. Only the Boston Red Sox and Cardinals have attracted more bets to win the World Series than the Cubs at the SuperBook.

Jeff Sherman, assistant manager at the SuperBook, said they have taken a handful of bets in the hundreds of dollars range on the Cubs, and a bettor at the MGM sportsbook placed a $500 bet on the Cubs to win the World Series when they were 40-1 in early November.

The Cubs are even a more popular bet at the 100-plus William Hill sports books in Nevada, where money has been bet on Chicago to win the World Series than any other team. William Hill took 11 bets on the Cubs at 40-1, including a $1,000 wager.

ESPN Chalk

PickCenterThe new ESPN Chalk section is now live. Check out betting coverage for all your favorite sports. Home page »

William Hill Senior Trader Adam Pullen moved the Cubs from 20-1 to 16-1 after the Lester signing.

"They are a popular team, and people bet them every year regardless of the odds," Pullen said.

Lester went 16-11 with a career-best 2.46 ERA with the Oakland Athletics and Red Sox last season.

Chicago finished 73-89 last season and had the third-worst ERA (3.91) in the National League.

The Cubs haven't had a winning record since 2009, but there is hope out of Hollywood: In the 1989 movie "Back to the Future Part II," the Cubs won the 2015 World Series.