MILWAUKEE — Forward Jabari Parker tried to get up immediately after falling to the floor with pain in his left knee.

But Parker stayed down, even with teammates trying to help. The way the leg buckled without contact, coupled with the grimace on Parker’s face, made it clear that this was much more than a minor injury the Milwaukee Bucks star could brush off.

Bucks’ official release

Parker suffered a season-ending left knee injury for the second time in three years, the Bucks said Thursday. An MRI confirmed the team’s worst fears after Parker got hurt with 6:34 left in the third quarter of Wednesday night’s home loss to Miami.

“He tore his ACL again. He’ll have surgery here coming up,” coach Jason Kidd said.

The recovery and rehabilitation period will take about a year, the Bucks said, meaning he will miss the beginning of next season.

Parker was averaging a career-high 20.1 points and 6.2 rebounds as one of the Bucks’ franchise cornerstones and the team’s second-leading scorer. Until Wednesday, he showed no signs that the knee was giving him trouble, consistently making explosive drives to the bucket. Parker went down after making minimal contact with his body with defender Luke Babbitt on a drive to the lane.

“It takes the spirit from you. Any time you see a kid like that go down.”

Bucks’ John Henson on Parker’s injury

An injury to the same ACL in December 2014 knocked Parker out of his rookie season after 25 games.

It was a devastating blow for the up-and-coming franchise.

“It takes the spirit from you. Any time you see a kid like that go down,” center John Henson said. “I think he’s the most improved player in the NBA. … Hopefully, the results are not as bad as it seemed with the injury and we go from there.”

The latest injury occurred on the same day that the Bucks welcomed back guard Khris Middleton, who missed the first 50 games of the year after tearing his hamstring in training camp.

Parker, Middleton and All-Star forward Giannis Antetokounmpo were supposed to be part of a young core that would lead the Bucks when the team moved into its new downtown arena in 2018. The faces of Antetokounmpo and Parker are draped on a giant poster on the side of a building outside team headquarters.

The Bucks were already struggling even with a healthy Parker and Antetokounmpo. They are 2-10 since moving to two games above .500 on Jan. 10, falling to 11th in the Eastern Conference playoff race.

The hope was that the return of Middleton would help give the Bucks a boost for the stretch run. A playoff push will be tougher now without Parker, Antetokounmpo’s running mate in the frontcourt.

Kidd is trying to focus on positives. The Bucks might be able to draw some confidence from the 2014-15 season, when they made a surprise playoff run despite losing Parker, the second overall pick in the 2014 draft out of Duke.

After hurting his knee that December, the hard-working Chicago native returned 11 months later, playing 76 games in 2015-16.

“I thought practice was spirited today. Understanding what we lost as a person and as a player, we’re all down,” Kidd said. “But we’ve gone through this before – not just with Jabari. It’s a next-guy-up mentality. We have to rally one another. It has to be a team effort to get out of this funk.”

Kidd is easing Middleton back into the rotation, intending to limit the guard to 15-20 minutes per game off the bench to start. Eventually, the Bucks could replace Parker with Middleton in the starting lineup.

For the short term, the Bucks could insert forward Michael Beasley into the starting lineup. The eight-year veteran is averaging 8.7 points off the bench.

Rookie 7-foot-1 forward Thon Maker, the team’s first-round draft pick in 2016, could also see more time, along with Spencer Hawes. A 7-footer who can shoot the 3, Hawes was acquired last week from Charlotte along with center Roy Hibbert in a deal for backup center Miles Plumlee.