NFL.com reported Russell has shed 50 pounds in recent months, and there is now "significant" interest from more than one team, according to a source. Russell is at 265 pounds, the same weight he was at when the Raiders selected him first overall in 2007.
On "NFL Total Access" on the NFL Network, it was reported Russell would like to sign with a team where he can learn under a veteran quarterback. If Russell doesn't sign with an NFL team within the next 30 to 45 days, he also would be open to signing with a CFL team.
In January, Russell told Yahoo! Sports that he didn't want to be remembered as a "bust" and that he would attempt a comeback. In addition to working at the TEST Football Academy, Russell's comeback was to include tutoring by former NFL quarterback Jeff Garcia on technique, Hall of Fame running back Marshall Faulk on reading defenses, and several other former players, doctors and trainers.
Russell, who last played in the NFL in 2009, won only seven of his 25 starts during his career with Oakland. He completed just 52.1 percent of his passes with 18 touchdowns, 23 interceptions, 15 lost fumbles and a passer rating of 65.2.
He was paid approximately $39 million for his three seasons with the Raiders.
Russell was charged with felony possession of a controlled substance, a drink containing codeine syrup, when sheriff's officers raided his home in July 2010. A grand jury, however, ultimately declined to indict him on the charges later that year.
Former NBA player John Lucas had been serving as Russell's life coach in late 2010, but the pair severed their relationship in 2011.
Information from The Associated Press was used in this report.