Kendricks has already confessed and pled guilty to insider trading in a scheme, where he made more than $1.2 MILLION by plying a Goldman Sachs analyst with perks like cash and NFL tickets in exchange for private information.

Kendricks was cut by the Cleveland Browns after they found out about the charges during the NFL preseason -- but he was picked up the Seahawks shortly after ... knowing the league would probably suspend him.

In the 3 games he played in this season, Kendricks did well ... racking up 13 solo tackles and 2 sacks.

Now, the league has suspended him indefinitely while Kendricks waits for the sentencing phase (which is scheduled for January).