Michal Kempny’s offseason was essentially spent rewiring his own brain.

After Kempny experienced three major injuries to his left leg in the last two and a half years, his central nervous system — which controls most functions of the body and mind — had essentially forgotten that it worked.

Tests and exercises with a trainer early this summer showed the cerebellum in Kempny’s brain — the part that coordinates movement — wasn’t doing its job. That’s when Kempny’s long rehabilitation process — both for his leg and his own mind — began.

However, after a long summer filled with rehab and workouts plus the entirety of training camp, on Saturday, the Capitals assigned Kempny to the team’s American Hockey League affiliate in Hershey, Pa. (pending waivers). It was an indication they believe that Kempny needs more time to get up to speed and also let them clear up $1.125 million of Kempny’s $2.5 million salary this season. It’s just another setback in his NHL comeback.

Kempny’s long list of injuries started with a torn hamstring in 2019, which weakened the leg and made it more susceptible to another issue. That next problem came in 2020, when he had surgery to repair a torn Achilles’ tendon. In May 2021, he suffered a medial collateral ligament sprain, once again in his left leg.

Kempny’s trainer, Dominik Kodras, said he was focused on rehabbing Kempny’s left leg this offseason, working on the nerves on the injured side of his body. But he also worked on reminding the brain about Kempny’s leg.

“We did all these drills to activate certain parts of the brain just to tell the body, ‘Hey here is your leg, it’s actually good; there is nothing you should be worried about,’ ” said Kodras, the strength and conditioning coach for the Czech Republic national team.

Kempny spent three hours in the gym every day in the first three to four weeks of training and only worked on unilateral exercises, which help with balance and stability. He also adjusted his sleep and nutrition habits.

After the first four weeks, Kodras incorporated strength work and upped Kempny’s workouts to twice a day, taking care to maintain balance in the muscles of both legs, so that one wouldn’t be substantially stronger than the other. There was also some on-ice training, but that work mainly fell to Kempny’s skills coach in Prague.

By the end of the summer, Kempny had gained a considerable amount of muscle back on his legs. Fast-forward to October, and both parties believe the offseason work paid off.

“The main difference right now is that the brain knows that the leg is healthy,” Kodras said. “That is the main and only reason we all did it. Right now he is pretty much all set to do everything in the gym.”

Kempny, who last played an NHL game in August 2020, says he is now “100 percent pain-free.” However, being recently assigned to Hershey, he will not be in the lineup when Washington opens its season Wednesday night against the New York Rangers.

Kempny used to be the top-pair defenseman who helped the Capitals win the Stanley Cup and a valuable top-four asset to the left side of the defense. But now, unable to get back up to speed once again, he will continue his trek back to the NHL in the minors.

“For somebody that has been off for two years, I think he is looking to get more comfortable with everything,” Capitals Coach Peter Laviolette said. “Reads defensively, making reads in small areas, how quick the game is, the transition of the other team’s offense to defense, just catching that train that moves pretty quick out on the ice.”

With the physical pain out of the way, the focus is still on Kempny’s on-ice reads and mental performance.

“It is not a case of ‘Can he do it?’ ” said assistant coach Kevin McCarthy, who works with the defensemen. “It is just a matter of getting comfortable again, and, obviously, his skating, his work ethic, that is something you don’t have to teach, and he has that, and that is what allows him to be a good player.”

Kempny was physically close to coming back this past postseason before he suffered an accident that resulted in an MCL sprain. While Kempny was on a minor league conditioning stint in May in Hershey, an ice shoveler tripped on a towel on the ice. The ice shoveler tumbled into Kempny’s left knee, turning it inward.

Kempny was out for about 10 days with the Grade 2 MCL knee sprain. At that point, he decided to give up on that season and focus on the next.

“In that moment I just, I don’t know if I should laugh or cry,” Kempny said at the start of training camp. “It was bad luck. I believe that everything bad is behind me and I am just trying to focus on what is now.”

After the knee sprain, Kempny decided to change trainers and began to work with Kodras. Kodras and Kempny still talk every day, with Kodras checking in to make sure Kempny’s leg and brain are still working as one.

Now, all those conversations will continue in the minors — for now.

This story has been updated