Hamilton Tiger-Cats quarterback Zach Collaros was on the field throwing the ball for the first time since suffering a head injury in Week 2, but his coach has ruled out a return for Week 5.
Ticats head coach Kent Austin says Collaros will not play this week and that the team will evaluate Jeremiah Masoli and Dan LeFervour throughout the week.
The Tiger-Cats host the Ottawa Redblacks on Saturday.
Collaros, who was not wearing pads during the workout, was injured when he was involved in a helmet-to-helmet hit with Edmonton Eskimos defensive end Odell Willis.
The 25-year-old Collaros lay motionless for a time before leaving under his own power.
He missed last week's game against the Calgary Stampeders and there is no timetable for his return.