Source: Jackson's new deal could be worth as much as $49.3 million

ST. LOUIS -- St. Louis Rams running back Steven Jackson signed a six-year contract Thursday and was on the field for practice after completing a physical.

"It was great to see him," coach Scott Linehan said. "There's no upside to being adversarial in these kind of deals. You've just got to stay positive and you've got to focus on who's here and have trust and faith in the people that are working on getting everything done."

Jackson agreed to a two-tiered deal with the Rams. It's either a three-year extension worth $29.3 million with $21 million guaranteed, or a five-year, $49.3 million contract that includes huge escalators in Years 4 and 5, a source told ESPN.com's John Clayton.

The way the contract works is that it is structurally a five-year deal lasting until 2013. The final two years can be voided based on Jackson's performance, but his performance can also trigger the escalators to take the five-year deal to $49.3 million.

Though a breakdown of the triggers of the deal isn't fully known, a source told ESPN.com that Jackson has to perform similarly the next three seasons to the numbers he put up from 2005 through 2007 to fulfill the escalators.

Linehan, who conducted a month of practices without the centerpiece of the offense, joked that he gave Jackson "a big hug" and then asked for a loan. Offensive tackle Orlando Pace, no stranger to holdouts, said he was happy "big time, big time" to see the bruising runner. Defensive tackle La'Roi Glover said simply, "Things are pretty good at Rams Park right now."

Jackson rushed for 3,576 yards and 26 touchdowns the past three years and caught 171 passes for 1,396 yards and six touchdowns. In the prime of his career, Jackson is figuring he can equal those numbers and become a free agent by 2012.

After the 2011 season, Jackson would be only 28 and still have a chance to hit the free-agent market at a time he believes there might be a new collective bargaining agreement.

To get this deal, Jackson held out and accumulated about $400,000 of fines while out of camp. He held out long enough that he wasn't able to use 2008 as an accrued season counting in his years toward free agency.

By doing the three-year extension, Jackson doesn't have to worry. If there is no salary cap in 2010, Jackson would have enough years in the league to qualify for free agency for the 2012 season. His biggest accomplishment, though, was becoming the league's highest-paid running back, along with staying with the Rams.

The 235-pound Jackson ended his holdout on Wednesday.

"All things are forgiven," he said. "Some people don't agree and some people do agree and that's just what it boils down to during a holdout. Before I made the decision to hold out I took that into consideration."

Jackson is the centerpiece of the Rams' offense and had been entering the final season of a five-year, $7 million deal he signed as a first-round pick in 2004.

Linehan said Jackson would be in uniform for Saturday night's preseason game against the Baltimore Ravens but would not play. He said that although Jackson reported in good shape, he needed to condition his body for football.

"Really, you can't simulate the game," Linehan said. "It's more the conditioning factor of starting and stopping and getting in the huddle and doing all that. We have plans to do some extra things with him, even when we're not practicing."

Jackson told the St. Louis Post-Dispatch in a story on its Web site that the stalemate had been about a difference in philosophy. He said talks "recommenced" late last week, and Jackson booked a flight from Las Vegas to St. Louis on Wednesday when a deal appeared imminent.

"No one gets 100 percent of what they would like to happen, but me and my agent are happy," Jackson said. "Of course, there were heated debates on the phone but no one attacked publicly. I still feel the same way about this organization as I did last year the last game of the season."

He had his third consecutive 1,000-yard season in 2007 despite missing four games with injuries.

Information from ESPN.com's John Clayton and The Associated Press was used in this report.