It doesn't take long after watching Koa Farmer of Sherman Oaks Notre Dame compete to conclude that he's one of those special athletes who makes a difference.

Farmer, a starter last season as a junior at receiver and defensive back, will add some quarterback duties to his responsibilities this fall. The Knights will try to take advantage of his speed, toughness and versatility.

"He does a lot of things very well," Coach Kevin Rooney said. "He's a big, fast, strong guy with great hands."

Farmer's father, Jamal, was a standout running back during his days at Granada Hills High.

Farmer, 6 feet 1, 195 pounds, has committed to Cal as a defensive back. He'll be in action on Saturday when Notre Dame plays in the Edison seven on seven tournament in Huntington Beach beginning at 9 a.m.

Eric.sondheimer@latimes.com