Jackson traveled to Seattle on Tuesday to visit the Seahawks and take a physical with the two-time reigning NFC champions.
Seahawks coach Pete Carroll confirmed that Jackson was visiting with the organization but said no deal had been reached as of Tuesday afternoon.
"This is a visit for us. This isn't a signing," Carroll said. "This is a visit for us with Fred. We have tremendous respect for this player. He's got obviously a wealth of background. He's tough, he's smart, he's sharp.
"So we need to see where he is right now at 34 years old and see what he looks like. He's got a big physical coming up today, and we'll talk to him later. For those of you that have already made the decision on what's going on, we have not made that decision at all at this point. But we love that he's here, and we're trying to just get our ducks in a row for what may be necessary later on."
Jackson, an eight-year veteran, became a free agent Monday, when the Bills cut the respected team leader and fan favorite.
Jackson and Lynch have been close friends since 2007, when both broke into the NFL with the Bills. Lynch was Buffalo's first-round pick, and Jackson made the Bills' roster after spending the previous year on the team's practice squad.
The two shared starting duties during the 2009 season, and Jackson took over as the starter after the Bills traded Lynch to Seattle.
The two have stayed in touch, with Jackson noting that he and Lynch exchange texts regularly. At age 34, Jackson was the league's oldest running back last season.
The Bills restocked their backfield by acquiring LeSean McCoy in a trade with the Philadelphia Eagles in March. Jackson also was set to make a $2.5 million base salary in the final season of his contract, a price that was deemed expensive for a backup.
Although slowed by injuries the past few years, Jackson is a versatile rusher and receiver as well as a dependable blocker. Jackson's 5,646 rushing yards rank third in Bills history; he is fourth with 30 rushing touchdowns.
ESPN Seahawks reporter Sheil Kapadia and The Associated Press contributed to this report.