The Argonauts tweeted on Thursday:
Williams was selected with the No. 10 overall pick in the 2005 NFL draft by the Detroit Lions. He played 56 games over five seasons with the Lions, Oakland Raiders and Seattle Seahawks.
In 2010, he rejuvenated his career in Seattle under former USC coach Pete Carroll's watch, catching 65 balls for 751 yards and two touchdowns, but he followed that up with only 236 yards and one touchdown in 2011.
The 6'5" wideout hasn't played professional football since being released by the Seahawks in July 2012.
Williams, 29, will now try to find success with the reigning Grey Cup champions in Canada. The Argonauts went 9-9 last season, but ended up winning the championship with a formidable 35-22 victory over the Calgary Stampeders.
Will Mike Williams succeed in the CFL?
It must be a tough pill for Williams to swallow.
There was hope for him after the 2010 campaign, but he quickly reverted back to the bust of yore in 2011. He was a star coming out of USC, when he totaled 176 receptions for 2,579 yards and 30 touchdowns in two years at the university.
However, he learned the hard way that the NFL is a whole different ballgame.
Williams is getting older. Any hope of him finding success in the NFL appears to have evaporated. But he has a chance to win a Grey Cup with the Argonauts in Canada, and he can either look at this as an opportunity, or fail to ever live up to his potential coming out of college.
This is another opportunity for him to prove he can still contribute at a high level.