Content warning: This story contains mentions of gun violence.

For most players coming into the NFL, achieving success on the field is their primary motivator, but for Washington Commanders' Nigerian defensive tackle Haggai Ndubuisi, it's more about helping his mother.

While Ndubuisi finally got the sack he had been dreaming of for years in the Commanders' 13-6 preseason defeat to the Miami Dolphins, his biggest dream is to bring his mother to the US and help her recover from the gunshot wound which changed her life.

Lagos-born Ndubuisi still knows little of the shooting in Nigeria which wounded his mother's leg and changed his family's life - as he tells it, some details have deliberately been concealed from him for his own protection.

What he feels confident in saying, though, is that she has not had access to the healthcare she deserves. This is a fundamental motive behind the defensive tackle's NFL career, which is entering its third season as he signed for the Commanders' practice squad late last month.

An emotional Ndubuisi told ESPN: "When we were back in the North [of Nigeria], she was shot in the leg... We had an encounter back in the North and the wound just refused to go.

"It was not healing properly - I think maybe they [gave] wrong medications. It went deep into her leg and it was making her uncomfortable to walk.

"This has been going on for years and years. She has been going on medication - from one medication and hospital to the other. It breaks my heart that she's not getting the best treatment that she could get.

"I feel like this (American football) could help me bring her to the States so she can get the best treatment she can get because she has eye issues [too]."

He continued to speak on the impact his mother has had on him: "I feel like it's all I got - you just have one mom, you know. She taught me a lot of things. With her, she taught me that when I meet mothers, I respect mothers.

"I believe in karma. She always told me: 'My son; karma is real. Treat people the way you want to be treated.' This has always been my policy - I treat people how I want to be treated and I don't treat people how I don't want to be treated.

"I treat mothers how I want people to treat my mom, wherever she is, because I'm not there to be with her and I treat ladies how I want people to treat my younger sister because I'm not here with her."

Ndubuisi - the towering 23-year-old standing at 6-foot-7 and weighing an imposing 148kg - has trouble recalling the specific timeline of his mother's injury, although he says with certainty that he was a young boy and the family had yet to relocate to Lagos.

The injury prevented Ndubuisi's mother from working. As a child, he took whatever work he could find in an effort to help ease the pressure on his parents, four brothers and sister - everything from hawking water sachets to washing cars to working on construction sites.

Then, Ejike Ugboaja, who was drafted by the Cleveland Cavaliers in 2006 and has a foundation which aims to take children off the streets through sport, spotted Ndubuisi in Lagos for his basketball talent and later relocated him once again to Abuja.

Initially a soccer player like most young Nigerians, Ndubuisi's size and strength led him towards hoops. Getting the money together to arrange a Visa to showcase his basketball skills abroad proved a stumbling block, but by the time he solved that problem, Ugboaja had converted him to a new sport - American football.

Ugboaja told ESPN: "When [basketball] didn't work, I know God was doing something in his life, to be honest... Even when Osi Umenyiora came, Osi saw him and said: 'This guy is a football player, man. This guy is going to play football'.

"I already know that was his dream - that was what God kept for him. That was why he never [succeeded in getting] those Visas for all the basketball stuff. As soon as [he saw him], Osi said: 'I think this guy is my first pick right now.'"

Ndubuisi watched YouTube videos of his new sport to gain an understanding, before Ugboaja's partnership with Osi Umenyiora earned the rising star an invite to the 2021 NFL International Combine in London.

From there, Ndubuisi traveled to the US for the International Player Pathway Program (IPPP), but before allocation, he was picked up by the Arizona Cardinals ahead of the 2022 season - initially as an offensive tackle.

"Before the IPP could allocate, I got signed to the Arizona Cardinals. The GM happened to stop by the facility and he saw me training and they signed me up immediately to the Arizona Cardinals," he recalled, describing it as a "dream come true".

Ndubuisi was released during preseason and returned to the IPPP, where he converted to the defensive line - taking yet another crash course in the fundamentals and starting from scratch.

In his second NFL season, he was allocated to the Denver Broncos, but once again, his on-field contribution was limited to preseason. Ndubuisi later joined the Broncos' practice squad. In February this year, he was signed by the United Football League's (UFL's) San Antonio Brahmas, but waived due to his Visa not being updated in time, as per his account.

Undeterred, Ndubuisi worked out with the Washington Commanders and earned the respect of Dan Quinn - a head coach who knows all about great defensive players, having earned his stripes as a defensive lineman himself, and then later a defensive line coach and a defensive coordinator.

"The head coach called me and was like... 'I would like to see you and work you out and we can see where they go from there.' When I got invited, I flew on [the] Friday night - I flew on [the] Friday and they worked me out on [the] Saturday," Ndubuisi said.

"After my workout on [the] Saturday, they were impressed about the stuff [I did] and they were ready to sign me straight away after their workout with them. They were excited and they wanted to give me a trial... because I'm the kind of person they need."

Ndubuisi faced an uphill battle to make enough of an impression in preseason to be retained. He made two tackles in the 20-17 defeat to the New York Jets and then finally, a sack against the Miami Dolphins on quarterback Mike White. This, he had been dreaming of every day.

He said: "Every time I put myself on the line, all I visualize is getting that sack on the quarterback [and] making sure I impact on the O-line guy and make him not able to compete - destroy his willingness to compete and make him [think]: 'No. This guy is too tough.'

Ultimately, he was signed to the Commanders practice squad, but nothing motivates the 23-year-old quite like the prospect of improving the lives of his family.

"They pray for me every time I call them... [They] try to pray for an injury-free game. They're my source of strength, because at the end of the day, I am doing this for them, for myself and my community," he said.

"I tried to be the best I could, because for me, there's no room for failure."

The NFL airs live on ESPN's channels in Africa (DStv 218 and 219, Starsat 248), as well as repeats and highlights.