The 21-year-old who lost his leg during a car accident involving Haywood Highsmith earlier this month is now suing the NBA player … claiming the hooper’s careless driving caused the entire tragedy.

Alekxei Pino filed the lawsuit on Friday in Florida … alleging he was helping assist a stranded motorist on Feb. 6 in Miami when Highsmith barreled into him in his 2021 Audi A5 at a high rate of speed.

Pino claims in the suit Highsmith was going over the roadway’s legal speed limit before he hit him … causing an above-the-knee amputation.

Pino also claims he suffered other significant injuries in the crash … and has since undergone numerous medical procedures to address the damage.

Pino’s attorney, Manuel Dobrinsky, said in a statement this week his client is actually still in the hospital recovering … “with a very long road of rehabilitation ahead of him.”

Pino and his lawyer are asking for unspecified damages but estimate it will be in excess of $50,000.

Pino’s family, meanwhile, has also set up a GoFundMe, hoping to raise $100,000 to help him with the recovery process.

As we previously reported, cops said in a police report Highsmith was traveling 45 MPH in a 40 MPH zone before the accident a short time after the Heat beat the Orlando Magic at the nearby Kesaya Center.

Cops stated in the docs they believed drugs and alcohol were not involved … though they did say Highsmith may have been distracted by unknown circumstances. They ultimately cited him for careless driving.

The Heat said in a statement following the crash that their “hearts go out to those who were injured.”

Highsmith sat out of the Heat game the night following the wreck … although he returned to the floor on Feb. 11 against the Celtics, and played 23 minutes.