Chris Sale Red Sox
Chris Sale pitches against the Minnesota Twins on Oct. 2, 2016 at U. S. Cellular Field in Chicago. Getty

The 2017 MLB season is still a few months away, but it’s clear who will be the top challengers to the Chicago Cubs. The Boston Red Sox have emerged as the No. 1 contenders in the American League and a real threat to the defending champions.

Most of baseball’s top free agents remain unsigned, but Boston made the biggest move of the offseason Tuesday. The Red Sox acquired starting pitcher Chris Sale from the Chicago White Sox, bolstering a rotation that already included the 2016 AL Cy Young award winner. Boston’s World Series odds went from 10/1 to 5/1 at the Westgate Las Vegas SuperBook, and only Chicago has a better chance to win the title at 3/1.

Sale went 17-10 with a 3.34 ERA with the White Sox last season, posting at least 208 strikeouts and a 3.41 ERA for the fourth consecutive season. He joins a team that won 93 games last season but was swept in the first round of the playoffs by the Cleveland Indians. Cleveland nearly defeated the Cubs in the World Series, but they are now the AL’s second-best team behind the Red Sox.

Boston’s rotation had a 4.22 ERA in 2016, and that’s almost certain to improve with Sale, Rick Porcello and David Price entering 2017 as the team’s top three starters. Having one of MLB’s best pitching staffs will make the Red Sox very difficult to beat, considering they already have MLB’s top offense.

“Boston is the Golden State Warriors of baseball now,” New York Yankees general manager Brian Cashman said Tuesday at baseball's winter meetings. “They've got their Durant and Green and Thompson and Curry.”

After winning a record-setting 73 games and losing in the 2016 NBA Finals, the Golden State Warriors added Kevin Durant, probably the league’s second-best player. They have the best record in basketball with more than one-fourth of the season completed, and they are the heavy favorites to win the 2017 championship.

The Red Sox might not set any records next year, but the chances of them falling short in the playoffs are much smaller than they were a few days ago.