Jalen Rose and David Jacoby react to Khris Middleton becoming a free agent after declining his option with the Bucks. (1:45)

Milwaukee Bucks All-Star forward Khris Middleton is declining his $13 million player option and will become an unrestricted free agent, his agent told ESPN on Wednesday.

The 27-year-old Middleton is represented by Mike Lindeman of Excel Sports.

Middleton and the Bucks are planning to work together toward a new long-term deal, league sources said. Middleton is expected to command a max contract with Milwaukee or elsewhere. He is eligible to sign a five-year, $190 million deal to stay with the Bucks, or a four-year, $141 million contract with another team.

Middleton is the Bucks' top priority in a free-agent class that includes Malcolm Brogdon, Brook Lopez and Nikola Mirotic.

Middleton emerged as the co-star to MVP front-runner Giannis Antetokounmpo on a Bucks team that had the best record in the NBA and reached the Eastern Conference finals. Middleton averaged 18.3 points, six rebounds and four assists last season and made his first All-Star team.

He's a career 39% 3-point shooter, a self-made player who emerged from being a second-round pick to the Detroit Pistons out of Texas A&M into one of the NBA's elite wing players.