Uncertainty remains as to when rehabilitating tailback Willis McGahee actually will play for the Buffalo Bills, but the two parties Tuesday ended speculation over how his future is viewed, reaching agreement on a four-year contract that includes an option for a fifth season.

The deal, with most of the major components essentially agreed to during a Saturday afternoon negotiation session in Baltimore between McGahee's agents and top Buffalo officials, ends a 20-day training camp holdout. The two sides hammered out the final details of the contract on Monday and Tuesday, and McGahee is scheduled to travel to the Bills training camp on Wednesday.

McGahee will sign a contract that, counting all incentives, could be worth as much as $15.528 million. In bonus money, he will receive $4.15 million. That includes an initial $1 million signing bonus, a guaranteed option bonus of $2.75 million due next March, and a $400,000 roster bonus.

The "base" contract, minus incentives, is worth $7.053 million.

"From the outset of negotiations, the Bills never tried to penalize Willis for his injury, and that was a key," agent Drew Rosenhaus said. "They showed us a lot of respect and it's clear they believe Willis is a big part of their future. There weren't any discussions about, 'What if he doesn't (recover)?' They know he's going to be a player."

It was key, however, for McGahee to have certain guarantees in the contract. Example: If the Bills place McGahee on the non-football injury list, which is a consideration, they are technically not obliged to pay the former University of Miami star his $411,000 salary for the 2003 season, but they have agreed to do so.

McGahee, of course, still is rehabilitating from a catastrophic knee injury suffered in the Fiesta Bowl seven months ago. The injury, coming in the national championship game loss to Ohio State, included at least partial tears to three of the four knee ligaments.

Had McGahee been healthy, there is little doubt he would have been among the top three players chosen in this year's draft. Buffalo selected him with the 23rd overall pick instead of defensive end Chris Kelsay of Nebraska and Tennessee tight end Jason Witten, two other prospects it had virtually even with McGahee on its draft board. Ironically, the Bills still were able to land Kelsay in the second round.

McGahee -- who rushed for 1,753 yards and 28 touchdowns in 2002, his only season as a starter -- is making a remarkable recovery. Rosenhaus insists his client is ready to return to the field sometime this season, but Buffalo president and general manager Tom Donahoe and the Bills organization espouse a more prudent approach. The club likely will place McGahee on the physically unable to perform list or non-football injury list.

"We're not going to rush anything," Donahoe told ESPN.com over the weekend. "We're not going to jeopardize his career. We'll be very smart about how we handle things."

From the beginning of negotiations, sources told ESPN.com that the Bills were willing to include strong "backside" escalators to reward McGahee for his production. The tradeoff they wanted was a deal that ran at least five years, which they basically achieved.

For their part, McGahee and his representatives received escalators and incentives that can be worth more than $8 million based on performance. And because of the injury that could well sideline McGahee for much or all of this season, most of the "backside" money is based on what the tailback does after his rookie year.

The other tailback chosen in the first round, Larry Johnson of Kansas City, has a deal that includes only about $2 million in incentives. If McGahee were to cash in on all the extras, which is unlikely but not unfathomable, his contract would be worth more than many of the deals negotiated for players chosen ahead of him.

A major breakthrough in discussions came during the Saturday session. Rosenhaus was accompanied by his brother/partner, Jason, while Donahoe and team vice president Jim Overdorf represented the Bills in the 2 ½-hour meeting. The two sides left that meeting optimistic a deal would be consummated early this week.

With the McGahee agreement, just one first-round pick, Jacksonville quarterback Byron Leftwich, remains unsigned. There are two unsigned draft choices outside of the first round, Cleveland fourth-round tailback Lee Suggs and quarterback Drew Henson, who was chosen in the sixth round by the Houston Texans.

Henson is playing in the New York Yankees' minor league system and repeatedly has said he will continue with his baseball career.

Len Pasquarelli is a senior writer for ESPN.com.