SAN FRANCISCO (CNN) -- The Richmond High School Oilers are perfect on the court, but some are stumbling in the classroom.
So despite his team's 13-0 record, Coach Ken Carter locked out his players: no practice, no games until grades improve.

"These young men will play basketball maybe, if they're lucky, another two or three years," Carter said. "But if they don't get a decent education, it's a lifelong thing. We're going to have some problems."

Players at Richmond sign a 19-point pledge of good grades and perfect attendance. Players also pledge to study 10 hours a week and to sit in the front row in class. And they have backed their coach's call.

"It's not guaranteed that you're going to make it in the basketball business, but if you've got the grades, you've got something to fall back on," said sophomore Duane Harley.

Sophomore Damien Carter added, "Education comes first, and we haven't been handling our business in the classroom."

And senior Wayne Oliver noted, "It's hard, but I know what I have to do to get what I want."

Carter checks grades every two weeks. When some fell short, he postponed one game and threatened to forfeit next week's league opener.