The Hamilton Tiger-Cats placed quarterback Zach Collaros on the six-game injured list Monday, the CFL team confirmed Monday. 

Collaros has been out with head and back injuries after taking a hard hit from Edmonton Eskimos linebacker Odell Willis in a 28-24 loss on July 4. Collaros was flattened on the play after taking a helmet to the chin area.

The league fined Willis for the high hit.

Backups Jeremiah Masoli and Dan LeFevour have split time under centre for the 1-3 Tiger-Cats.

Collaros, a 25-year-old native of Steubenville, Ohio, was tabbed as the No. 1 quarterback after signing with Hamilton in the off-season. He has completed 23 of 41 passes for 212 yards, one touchdown, and two interceptions through two games this season.