Ray's status for the game has been in question since he suffered a lower-body injury in a 35-19 win at Winnipeg on July 19.
"I’ve been taking the reps all week so I was kind of expecting it," Collaros said Sunday at practice. "I'm just ready to go and I'm excited, it is my first start in a while."
Collaros, 24, spent most of last season on the injured list and sat No. 4 on the depth chart behind Ray, Jarious Jackson and Trevor Harris.
Collaros said he's looking forward to the first start of his two-year career.
"It's very special. It is a lot different than coming in in the fourth quarter. It is a completely different thought process and preparation before the game, so I’m just anxious and ready to go."
The Argonauts (2-2) enter a bye after Tuesday, which should give Ray time to heal.