A significant feature of the deal will be the appearance of casino operator's logo at Fenway Park, while MGM Resorts will also advertise on Red Sox radio and other media outlets.
The deal was facilitated by Fenway Sports Management, owners of Boston Red Sox and other sports teams.
MGM Resorts has already exerted considerable influence within the field of baseball sponsorship, with MLB teams due to wear MGM Resorts patches during the league’s opening series in Japan later this month.
MGM Resorts Chairman and CEO, Jim Murren, said: "We are excited to enter into this historic partnership with the Boston Red Sox.
"Combining the two iconic brands of the Red Sox and MGM Resorts will create a new one-of-a-kind fan experience for baseball fans unique to not only New England and MGM Springfield, but the rest of the country."
