Toronto linebacker Marcus Ball has been placed on the six-game injured list.
The 30-year-old was hurt in the Argonauts Week 15 win against Hamilton.
He has played in 14 games making 57 tackles, recording two interceptions and one forced fumble.
Ball has been a large part of the Argos turnaround on defence with a number of new faces and defensive coordinator Corey Chamblin putting it all together.
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Saskatchewan Roughriders
Video: Why the Riders paid up to sign former NFL punter and Regina native Jon Ryan
Hamilton Tiger-Cats
Why the Ticats released receiver Jalen Saunders
Edmonton Elks
Video: Are the Redmen and Eskimo nicknames racist?
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