The Red Sox announced Wednesday that they’ve issued an invitation to four Minor League clubs to become the organization’s affiliate under MLB’s new player development structure.

Those clubs are: the Worcester Red Sox (Triple-A), Portland Sea Dogs (Double-A), Greenville Drive (Class A Advanced) and Salem Red Sox (Class A).

“We are pleased that Worcester, Portland, Greenville and Salem have been invited to continue their affiliation and will remain part of the extended Red Sox family,” said Red Sox president and CEO Sam Kennedy. “Our farm system is an essential component in our work to create a more consistent and efficient operation that helps us play October baseball each and every year. We thank our affiliates for the significant role they play in shaping our future stars, and look forward to continuing our relationship under MLB’s improved player development structure.”

This is the first year for the Worcester Red Sox, ending Boston’s Minor League relationship with Pawtucket, R.I., that started in 1970. Pawtucket had served as the Triple-A affiliate for the Sox since '73.

The move from Pawtucket to Worcester had already been underway long before MLB’s restructuring of player development affiliates.

The obvious perks of having a Triple-A team in Pawtucket for so long was the ability for the Red Sox to summon prospects for a game at Fenway Park at the last minute when necessary, as well as for Boston fans to have a short drive to go watch the team’s top prospects.

Those perks will still be in play in Worcester, which is less than 45 miles from Boston.

And the WooSox will play in a state-of-the-art new venue called Polar Park.

“We are very pleased to be invited to enter into a long-term agreement with the Boston Red Sox,” said Dr. Charles Steinberg, president of the Worcester Red Sox. “In this, the deep depths of December, we all long to see the next generation of Red Sox stars take the field and bring us joy.”

The other three affiliates are unchanged from previous years.

Double-A Portland's Hadlock Field is 107 miles from Fenway Park, giving fans easy access to see those players as well.

“We thank the Red Sox for continuing to place their trust in us and going forward, to giving our amazing fans more opportunities to see future big league stars in action, right here in Portland,” said Portland Sea Dogs president and general manager Geoff Iacuessa. “We appreciate the Red Sox's commitment to the Sea Dogs, the city of Portland and the state of Maine.”

The Greenville Drive (South Carolina) and Salem Red Sox (Virginia) aren’t nearly as close, but both franchises are thrilled to be remaining in the Red Sox family. One change under the restructuring is that Greenville will now be considered the Class A Advanced team. Under the previous arrangement, Salem held that distinction.

“Since the inaugural season of the Greenville Drive in 2006, our success has been built upon strong partnerships,” said Greenville Drive owner and president Craig Brown. “Our most important partnership has been with the Boston Red Sox. We have had the privilege of being part of Major League Baseball’s most storied organization for close to two decades, with our fans witnessing more than 90 players realizing their dreams by making it to the big leagues and playing for World Championships. We eagerly anticipate the return of baseball to Fluor Field this spring and welcoming the next group of Red Sox stars while we continue to build upon our unique partnership with the Boston Red Sox for years to come.”

“We are delighted by our continued affiliation with the Boston Red Sox, one of MLB’s premiere organizations,” said Salem Red Sox managing director Jeff White. “A more than decade-long partnership with the City of Salem, the entire Roanoke valley community and the loyal employees of the Salem Sox continues. In this most difficult of times, it’s a sign of continuity and hope, welcomed by all.”

The one team that was not invited to maintain their affiliation with the Red Sox is the Class A Short-Season Lowell Spinners. Lowell's LeLacheur Park is 33 miles from Fenway, and top prospects would often make their professional debuts at that affiliate soon after being drafted.

However, there is good news on the Lowell front.

The Red Sox, in conjunction with the city of Lowell, announced that they are doing everything they can to keep baseball in Lowell in 2021 and beyond.

The two sides are in the early stages of evaluating opportunities for the 2021 season, and they will continue to discuss long-term options in the weeks ahead.

“For over a year, we have worked with Congresswoman Trahan, Lowell City Manager Eileen Donoghue, Major League Baseball and Lowell Spinners ownership to examine every option that would keep baseball in the City of Lowell,” said Kennedy. “We are exploring what form that could take in 2021, and are committed to maintaining the 24-year-long tradition of baseball in the Lowell community. We are grateful to Governor Baker, Senator Markey and Senator Warren for their support of our collective efforts, and look forward to our continued work with Lowell’s public officials as we develop and formalize our plans.”

“I am grateful to the Red Sox for their commitment to continue to work with the City and officials to ensure that a 25th season of baseball will be played at LeLacheur Park,” said Massachusetts Governor Charlie Baker. “Baseball has been an integral part of recovering from national crises in the past, and maintaining baseball in Lowell will help ensure that it can play that role again for fans throughout in the Merrimack Valley.”