Spiller's deal is worth $25 million, but could escalate as high as $37.5 million if incentives are met, a source told ESPN.com senior NFL writer John Clayton. According to the source, the contract also includes $20.8 million in guarantees.
Spiller wasted little time upon arriving at the team's training camp complex in suburban Rochester, N.Y. He headed directly to attend team meetings before taking the field for the Bills' evening practice.
Selected ninth overall out of Clemson, Spiller has some catching up to do after missing 11 practices since camp opened July 29. He was also one of the final NFL first-round draft picks to sign this summer.
"Any time you miss any day, that's one day you can't get better," Spiller said. "Of course you miss that, but at the same time, you understand that you've got to get the business done first before you get on the field. And I'm glad I was able to get it done so I can get out there."
As for becoming a rich man, Spiller shrugged that aside.
"That's on the back burner now," he said. "Now my mind is focused on coming out here tonight and trying to get better."
Okung agreed Friday to a six-year, $48.5 million deal, including more than $29 million guaranteed, sources told ESPN senior NFL analyst Chris Mortensen.
The ACC's player of the year last season finished his four-year college career with 51 touchdowns, including 32 rushing. Listed at 5-foot-11 and 196 pounds, Spiller has dynamic speed and is unafraid to run up the middle.
Because of his versatility, Spiller has drawn comparisons to Reggie Bush of the New Orleans Saints. Spiller and Bush are the only two players to finish their college careers with 3,000 yards rushing, 1,500 yards in kickoff returns, 1,000 yards receiving and 500 yards in punt returns.
Spiller is being counted upon to play a big role in the new offense first-year coach Chan Gailey is installing. He'll be part of a three-back rotation that includes Fred Jackson and Marshawn Lynch, who split the starting duties last season.
Gailey hasn't ruled out the possibility of splitting Spiller wide as a receiver, or using a formation with two running backs.
Spiller received a loud reception from the crowd as he came out for practice, and gave a thumbs-up sign to a group of fans at the rail chanting "C.J.! C.J.!" Numerous fans were wearing No. 21 Spiller jerseys, and at least one waved a large Clemson flag.
Spiller then showed his tremendous burst on a running play to the right. As he broke past the line of scrimmage, linebacker Donovan Woods was late getting over, but grabbed a piece of Spiller's red undershirt. A strip of the shirt tore off in Woods' hand as Spiller blew past him.
"It felt great," Spiller said. "I've still got to get my timing down. First day in pads, so you really don't know what to expect. But the first day went pretty smooth."
Gailey said he intends to work Spiller in slowly.
"He's got a lot of catching up to do, not only mentally but physically," Gailey said. "But I mean you could see the explosiveness that he's always had."
The deal comes a day after Spiller celebrated his 23rd birthday.
"It's something that I'll always remember," Spiller said, noting he learned the deal had been agreed to on Thursday, shortly after he had a birthday lunch with his family in Lake Butler, Fla. "Whatever day, I would have always remembered it. But it's always special to do it on your birthday. It was a great feeling."
After practice Friday morning, quarterback Trent Edwards was pleased to learn of the news.
"I'm excited, honestly, because I feel like he's a big impact player on our offense and our team," Edwards said. "The potential is all there. He's got all the talent in the world, and it's just a matter of us blocking for him."
General manager Buddy Nix, Gailey and Bills owner Ralph Wilson all praised Spiller in the days after he was drafted.
Wilson referred to Spiller as "one of the best players in the country," and someone who could provide a spark to what he called a "dull team." Buffalo's offense has ranked 25th or worst in yards the past seven seasons.
WR Roscoe Parrish was hurt 90 minutes into practice when he pulled up short while running a route. He angrily walked off the field, throwing his shoulder pads to the ground, on his way to the locker room. Gailey wouldn't divulge the nature of the injury except to say "It's not bad," and Parrish should miss only a few days. ... LB Chris Kelsay practiced on a limited basis for the first time since hurting his right shoulder on the first day of camp. ... DT Kyle Williams missed both practices Friday, a day after hurting his right hand.
Information from The Associated Press was used in this report.