Milwaukee Bucks guard Khris Middleton will undergo surgery next week after suffering a torn left hamstring in a preseason workout on Tuesday, the team announced Wednesday.
He is expected to be sidelined for six months.
"We're obviously disappointed for Khris and our team, but injuries are an unfortunate part of the game," Bucks general manager John Hammond said in a statement. "We'll rely on our overall roster depth to help us while Khris is out for a significant period of the season."
Middleton, 25, averaged a career-high 18.2 points, 4.2 assists and 3.8 rebounds in 79 games last season for the Bucks, who finished 33-49 and failed to qualify for the playoffs.
Drafted by the Pistons with the 39th overall pick in 2012, Middleton was part of the trade that sent Brandon Jennings to Detroit the following year.
Middleton has blossomed with the Bucks, turning into a key player for a franchise on the rise that was hoping to return to the playoffs this season.
Training camp starts next week in Madison, Wisconsin. The estimated six-month timeline for Middleton's recovery means that he could return in mid-to-late March, with about a month left in the regular season.
Middleton apparently hurt the hamstring after attending a team news conference on Tuesday announcing a four-year, $100 million contract extension for forward Giannis Antetokounmpo. Last summer, Middleton signed a five-year, $70 million extension.
Antetokounmpo, Middleton and forward Jabari Parker are considered building blocks for a young team. The plan is for the Bucks to turn into a playoff contender by the time a new arena opens in downtown Milwaukee in 2018, with the trio leading the way.
For the 2016-17 campaign, Milwaukee might need last year's first-round draft pick, guard Rashad Vaughn, to help replace Middleton, a career 40 percent shooter from 3-point range. The Bucks also drafted guard Malcolm Brogdon from Virginia, who shot 39 percent from behind the arc as a senior, in the second round this year.
Milwaukee re-signed veteran forward Steve Novak, a 3-point specialist, in the offseason, as well.
The Bucks last qualified for the playoffs in 2014-15, making a surprise run in spite of a left knee injury that sidelined Parker for the final four months of that season.
The Associated Press contributed to this report.