Al Horford agrees to four-year, $109 million contract with Philadelphia 76ers

June 30 (UPI) -- The Philadelphia 76ers are signing veteran center Al Horford to a four-year contract, league sources told ESPN and the Philadelphia Inquirer on Sunday.

The five-time All-Star selection agreed to a four-year, $97 million deal with the Sixers, according to ESPN. He could make up to $109 million with championship bonuses.

Horford, 33, will leave the Boston Celtics after three seasons. He declined his $30 million player option for next season to become a free agent. The 76ers plan to put the big man at power forward alongside center Joel Embiid, according to ESPN.

Horford began his NBA career with the Atlanta Hawks, spending the first nine years of his career in Atlanta. He signed with the Celtics in 2016 and averaged 13.6 points, 6.7 rebounds and 4.2 assists per game with Boston this season.

The 76ers' deal with Horford came after Philadelphia agreed to a sign-and-trade with the Miami Heat involving Jimmy Butler. The Heat will send Josh Richardson to the 76ers as part of the deal.

The 76ers also reached a deal to retain forward Tobias Harris. He averaged 20.0 points, 7.9 rebounds and 2.8 assists per game in 82 regular-season contests this season.

NBA free-agent contracts can't be officially signed until July 6.