The Portland Trail Blazers have agreed to trade All-Star guard Jrue Holiday to the Boston Celtics, elevating the Eastern Conference arms race, sources told ESPN on Sunday morning.

The Celtics are sending center Robert Williams III, guard Malcolm Brogdon, a 2024 first-round pick via Golden State and a 2029 first-round pick to the Blazers, sources said.

The Blazers are stacking assets in the wake of the Damian Lillard blockbuster to the Milwaukee Bucks on Wednesday, a deal that brought them Holiday with an intention to trade him to the league's highest bidder over the weekend.

The Celtics were an aggressive suitor for Holiday, 33, and are expected to work to sign him to a long-term deal with free agency looming in the summer of 2024. The acquisition of Holiday could leap the Celtics over the Bucks as preseason favorites in the Eastern Conference.

Holiday is considered one of the league's best two-way guards, and his arrival with the Bucks played a huge part in the franchise's 2021 NBA championship. Holiday made the Eastern Conference All-Star team in 2023 after a nine-year gap between appearances that was the longest in NBA history.

The Blazers are expected to want to keep Williams to pair with new center Deandre Ayton, but Brogdon will likely be part of additional trade talks upon his arrival in Portland, sources said. Absent another trade, Brogdon will start the season with Portland. The Blazers are committed to a young group of guards including No. 3 draft pick Scoot Henderson, 2022 first-round pick Shaedon Sharpe, and Anfernee Simons, who signed a $100 million extension last summer.

Even before a potential Brogdon deal, the Blazers have a significant return to show for the Lillard trade: Ayton, Williams, Brogdon, and first-round picks in 2024 (via Golden State, protected 1-4), 2029 (Milwaukee unprotected) and 2029 (Boston unprotected). The Blazers also have pick swaps with the Bucks in 2028 and 2030.

Information from ESPN's David Purdum was used in this report.