ALAMEDA, Calif. - Playing football never crossed Isaiah Ekejiuba’s mind.

He joined the soccer team as a boy in his native Nigeria. As a teenager living in the United States, he played basketball and competed as a sprinter and jumper in track and field.

He had size and speed, but football was an American game he knew little about.

Then in the spring of 2002, an advertisement in the student newspaper at Virginia caught his eye: football tryouts. There began a most unlikely road to the NFL.

“A little backdoor into football,” Ekejiuba said with his friendly smile, sitting in the Oakland Raiders’ locker room before a recent practice. “My dad always used to watch football and I didn’t really understand the concept. I just wanted to see what it was like.

“I was already studying electrical engineering. The thought of football was just something to do after classes.”

Little did he know it’s a sport that demands all your time — practice, weight training, team meals and meetings, weekend travel, study sessions.

Ekejiuba is now an NFL rookie, contributing on special teams for Oakland. Even he is surprised at his career route considering academics were always No. 1 in Ekejiuba’s family.

Born in Benin, Nigeria, Ekejiuba came to the United States for good in 1995 for his late mother’s job. His mom, Felicia, received her doctorate at Harvard. A sociologist and anthropologist, she worked for the United Nations heading the Africa section of the U.N. Development Fund for Women, whose purpose is striving to eliminate violence against women in third-world countries and helping them gain equality.

“She always pushed academics first before anything else,” said Ekejiuba, who speaks the Nigerian dialect Ibo and is two classes shy of an electrical engineering degree he plans to finish soon.

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So, when he started playing football, everyone in the family was understandably shocked.

“I couldn’t believe it,” said his older sister, also Felicia. “It wasn’t like he had a background in that. My mother was kind of skeptical, too. Isaiah’s like her baby. We all supported his decision. I knew if he put his mind to it and worked hard he would achieve whatever he wanted.”

Ekejiuba joined the Cavaliers’ football team as a walk-on receiver during the spring of his sophomore year at Virginia. He suited up for eight games in 2002 but didn’t see any action until the following season. He shifted to defense and became a special teams standout in 2003, appearing in all 13 games. And as a senior last year, Ekejiuba earned a scholarship and received a team award as the school’s top special teams player.

“I am so happy for him,” said Corwin Brown, one of Ekejiuba’s college coaches who now works for the New York Jets directing the defensive backs. “It was something. I kind of remember it. He came at me, a tall, gawky guy. He could run and he had good size. You couldn’t help but think, ‘How come he hasn’t played and why is he just now coming out?’ I thought, ‘I don’t care if he’s never played before, if he could learn a couple things, he could be pretty good.”’

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Ekejiuba signed with Arizona as a rookie free agent in April after the draft and spent training camp and the preseason with the Cardinals before they released him in late August. He joined the Raiders’ practice squad Sept. 6, then got promoted to the 53-man roster last month to help Oakland’s injury-depleted defense when safety Derrick Gibson went on injured reserve.

Ekejiuba made his NFL debut against the Tennessee Titans on Oct. 30. At 6-foot-4 and 220 pounds, the 24-year-old Ekejiuba is a physical presence on special teams — too fast for some of the larger players to stop, and big enough to knock down the smaller ones.