The Boston Celtics agreed to a four-year, $30-million extension with guard Payton Pritchard, his agents told ESPN’s Adrian Wojnarowski. Pritchard’s new term will be fully guaranteed. The 25-year-old was on course to enter restricted free agency next summer. Selected 26th overall in the 2020 draft, the Oregon product is heading into the final year of his four-year, $10.5-million rookie deal.