The Boston Red Sox and Houston Astros have been installed as co-favorites to win the 2019 World Series, heading into an offseason that could see impactful free agents change teams and shake up the odds.

The Red Sox and Astros, the past two World Series champions, are each listed at 6-1 at the SuperBook at Westgate Las Vegas. The New York Yankees and Los Angeles Dodgers, two potential landing spots for prized free agent Bryce Harper, are each 7-1.