Jackson was quick to get out of town, signing a five-year, $55.55 million contract with Tampa Bay.
The Chargers also released left tackle Marcus McNeill due to a history of neck injuries and to clear cap space. There's still a chance the Chargers could re-sign McNeill, a second-round draft pick in 2006 who played in two Pro Bowls. McNeill missed the final seven games of 2011 with a neck injury. McNeill had to pass a physical by Thursday to qualify for his $10 million salary.
General manager A.J. Smith didn't return calls seeking comment.
The Chargers declined last week to use the franchise tag on Jackson, which would meant paying Jackson about $13.7 million next season.
Jackson's departure was not unexpected.
The 6-foot-5 Jackson had consecutive 1,000-yard seasons in 2008-09 before getting embroiled in a nasty contract spat that cost him much of the 2010 season.
Jackson's original five-year contract expired after the 2009 season. But because 2010 was an uncapped year, he would have needed six seasons to become an unrestricted free agent.
Unhappy that he didn't get a long-term deal, Jackson refused to sign a $3,268,000, one-year tender as a restricted free agent. He sat out the first seven games and then reported in time to serve a three-game suspension on the roster exempt list - he was placed there in a hardball move by Smith. He was on the active roster for the final six games to accrue a season toward unrestricted free agency.
When Jackson hadn't signed the tender by that June 15, the Chargers slashed their offer to 110 percent of his 2009 salary, or $583,000. Due to the games he missed, he made less than $300,000 in 2010.
In his first game back, Jackson lasted only two plays before limping off the field with a strained right calf. He missed the following game and finished the season with 14 catches for 248 yards and three touchdowns.
"It's huge," said Hardwick, who's entering his ninth season. "You just never know how it's going to unfold. Both sides kept working really hard. It got to the point where everything looked good and we said, `Let's go with this.' Ultimately, I'm very excited to be here. This is where I want to be. I want to finish it out here. That'd be a nice run."
Tuesday's move came less than two weeks after Hardwick's good friend, four-time Pro Bowl left guard Kris Dielman, retired after nine seasons due to the effects of a concussion.
It would have been a huge blow if Hardwick had left as a free agent.
"That's a lot of years of experience that would have been gone out the window," said Hardwick, who's been to one Pro Bowl. "I'm just excited to be back, to keep growing. We've made some really good strides here the last few years, as far as our abilities on the offensive line. We need to take this thing to another level, to keep evolving as a line and a unit."
The Chargers would like to re-sign left tackle Jared Gaither, who helped stabilize the line in the season's final five games after he was waived by Kansas City. Gaither became an unrestricted free agent on Tuesday afternoon.
"I'm just glad to be back and have a chance to work with Philip Rivers for the next several years and work with the guys on the line," Hardwick said. "We can make some pretty good waves. We have a lot of room for improvement. "It's going to be exciting, and we'll see how good we can get, and we have to get good in a hurry. We can't flop around at the first of year. We have a lot of hard work ahead."
San Diego tendered contract offers to restricted free agent Brandyn Dombrowski, an offensive lineman, and exclusive rights free agents Richard Goodman, a wide receiver, and Mike Windt, the long snapper, maintaining negotiating rights with the three players. Should Dombrowski receive a contract offer from another team, the Chargers will have a chance to match the offer. As exclusive rights free agents, Goodman and Windt cannot sign with another team.