ESPN.com's John Clayton reports Spiller's deal is for five years and $25 million with incentives that can pump the value to $37.5 million. Spiller received $20.8 million in guarantees. Spiller is expected to sign the contract Friday afternoon.
The Bills opened training camp at St. John Fisher on July 29 without the dazzling playmaker from Clemson. He will get carries out of the backfield but also will contribute as a slot receiver and return man.
Spiller was drafted to stimulate an offense that has ranked 25th, 30th, 30th, 28th, 25th and 30th over the past six seasons.
"You're going to be the No. 1 guy that gets us going," Bills owner Ralph Wilson told Spiller at the rookie's introductory news conference in April.
The Bills haven't made the playoffs in a decade, tying the Detroit Lions for the longest active drought.
"The Buffalo Bills for the last 10 years -- and this is my fault -- we’ve been a dull team, really dull," Wilson said. "It's no fun to go out there. I said to one of our coaches a few years ago, 'You know, there's no excitement.' He said 'Listen, if you win, that's all that counts. Winning.' The only thing is, we didn't win much. But we're going to turn that around."