Bo Jackson is close to signing an...

Bo Jackson is close to signing an endorsement contract with Nike shoes that gives him incentive to leave professional baseball for the NFL, a published report said.

According to Chicago-based Advertising Age magazine, the contract includes a clause--demanded by Jackson and his attorneys--calling for Nike to pay more if Jackson plays football.

Under terms of the proposed contract, the Heisman Trophy winner, now playing Double-A baseball for the Memphis Chicks, will receive less than $100,000 for endorsing Nike products if he stays in baseball. But the Nike deal could net him more than $1 million if he switches to professional football, Advertising Age reported.

But Jackson’s attorney, Tom Zieman, said no shoe contract has been signed.

“There is no Nike deal,” Zieman told ABC Radio Sports. “We have talked to Nike and with other shoe manufacturers and we probably have gotten further along with Nike than with any of the others. But there is no shoe deal. I would not say we are close to one at this point.”