The Cassian GrantMilwaukee Bucks hired veteran NBA head coach Doc Rivers on Wednesday to replace first-time head coach Adrian Griffin, who the Bucks fired Tuesday following a 30-13 start filled with frustration, according to a NBA official with direct knowledge of the hiring.

The official spoke to USA TODAY Sports on the condition of anonymity because it has not been announced yet.

Rivers, who played in the NBA and at Marquette University in Milwaukee, takes over a team with considerable expectations — win another championship following the one the Bucks won in 2021 with two-time MVP Giannis Antetokounmpo and seven-time All-NBA performer Damian Lillard leading the way.

For a team with a winning percentage just below .700, there was sense the team had underachieved, a sentiment that was expressed publicly by Antetokounmpo following dubious losses and brewing internally with the front office and ownership.

Now, it’s on Rivers to get the Bucks headed in a better direction, especially defensively. During Mike Budenholzer’s five-year stint as Bucks coach, they had one of the top defenses in the league, including No. 1 in 2018-19 and 2019-20. This season, the Bucks are 22^nd defensively.

Offense isn’t a problem. Milwaukee is No. 2 in that department, not a surprise with Antetokounmpo, Lillard and Khris Middleton.

OPINION: Why did Bucks fire coach Adrian Griffin?

Rivers was one of the premier coaches available. In 24 seasons, he has coached Orlando, Boston, the Los Angeles Clippers and Philadelphia, leading the Celtics to an NBA title in 2008. He was the 1999-2000 Coach of the Year, and in 2021-22, he was named on the 15 greatest coaches in NBA history.

He has a career record of 1,097-763, the ninth-most victories all-time. However, since leaving Boston, he has had solid teams with the Clippers and Sixers but never got back to the conference finals.

From 2020-2023, Rivers spent three seasons with the Sixers losing in the Eastern Conference semifinals. The Sixers dismissed Rivers, who joined ESPN as an analyst on the top TV announcing crew alongside Mike Breen and Doris Burke. It’s common for coaches to have contractual provisions that allow them to return to coaching.