The former Congress Street headquarters of the Maine Red Claws professional basketball team in 2013. The office is now located on Forest Ave.

The Boston Celtics announced Thursday that it has agreed to purchase the NBA G League’s Maine Red Claws, subject to successful finalization of the transaction and G League approval.

“Over the years, the G League and the Red Claws have become increasingly important to the Celtics and our player development efforts,” Celtics president Rich Gotham said. “We look forward to deepening both our ties with basketball operations and within the community and further bringing the Celtics experience to fans in Maine.”

Upon completion of the deal, the Portland-based Red Claws would be wholly owned by the Celtics as the team’s official G League affiliate.

“The Celtics have been great partners with the Red Claws over the last 10 seasons,” Red Claws chairman and principal owner Bill Ryan Jr. said. “We are thrilled that the Celtics will continue to build upon the success we have had in making the Red Claws an important part of the Maine community.”

Neither the Celtics nor the Red Claws plan to make any further comment until the completion of the purchase.