Collaros takes over as the starting quarterback after Argos coach Scott Milanovich dropped a bombshell Thursday, announcing incumbent Ricky Ray is out approximately six weeks with a shoulder injury.
Ray, 33, was injured in the first quarter of Toronto's 35-14 home loss to Calgary on Friday. After throwing the ball away, a scrambling Ray extended his right arm to brace his fall upon being hit by Stampeders' defensive lineman Charleston Hughes.
"Ricky has a partial tear (in) a muscle in his shoulder that's called the teres major, Milanovich said. "I've been informed that's not part of the rotator cuff.
"He's going to be out approximately six weeks. It could be a couple of weeks less or a couple of weeks more depending on he responds to his rehab."
The teres major muscle is located in the back of the shoulder. It helps rotate and extend the arm and damaging it causes pain in the back of the shoulder, back and upper arm.
Fortunately, Ray won't require surgery. But Toronto (5-3) — which tops the East Division ahead of Hamilton (4-4) and Montreal (3-5) — will be minus its offensive catalyst for an important stretch that includes a home-and-home series with the Alouettes and a western road trip to Regina, Calgary and Edmonton before hosting the arch-rival Ticats on Oct. 4.
"Pressure is what you make (of) it," Collaros said. "As long as we're prepared as a team and I'm prepared I think we all feel comfortable out there.
"We have a big home-and-away series with Montreal . . . we just have to get after it this week and be ready."
Ray missed three late-season starts last year with a knee injury before returning to lead Toronto on its Grey Cup march.
"Hopefully we get a similar result," Milanovich said. "It's part of the game, there's injuries in the sport of football and I have faith Zach, Trevor (Harris) and Josh (Portis) will go out there and win games for us.
"Obviously it's the quarterback and it's a different piece of the puzzle you have to replace but all teams prepare for this."
The six-foot, 216-pound Collaros is anxious to be Toronto's starter for the foreseeable future.
"It's not a good thing that had to happen under these circumstances," he said. "But I look forward to leading this team these next few weeks."
Collaros certainly has big shoes to fill. Ray has completed 148-of-189 passes (78.3 per cent) this season for 1,824 yards with 15 TDs and no interceptions.
Ray was especially sharp in his four last starts, completing 69-of-79 passes (87.3 per cent) for 907 yards and nine TDs before his injury. Toronto boasts the CFL's top passing attack (320.6 yards per game) and is third in scoring, averaging 30.5 points.
But the offence has struggled establishing the run as Toronto's ground attack is ranked last in the CFL (82.5 yards). That something Milanovich wants to improve upon regardless of who's at quarterback.
Collaros was impressive in his CFL starting debut. After a full week of practice replacing an injured Ray (knee), Collaros completed 21-of-25 passes for 253 yards and three TDs while adding 28 yards rushing July 30 in 38-12 home win over B.C.
Pressed into action versus Calgary with little prep time, Collaros finished 16-of-26 passing for 221 yards with an interception — Toronto's first this season.
"Last week really wasn't as much a function of him," Milanovich said. "One of the things I thought that hurt us against Calgary was we didn't run it very well or very often so we put pressure on Zach to drop back and make plays.
"The one thing I've talked to him about is just protecting the ball outside the pocket. You're going to throw an interception now and then, I can live with those, just make sure you've got two hands on the ball at all times."
Milanovich will give Collaros ample opportunity to lead Toronto's offence.
"I've told Zach the same thing I did against B.C., which was it's his game, there's no quick hook," Milanovich said. "I'm not waiting for him to make a mistake to put someone else in.
"Now if Zach were to not play well for an extended period of time we'd always have to do what's best for the team but it's his game. I don't anticipate that happening."
Those are reassuring words for the former Cincinnati Bearcats star.
"It makes you feel good to know they trust you," Collaros said. "I think that's a product of me coming to work every day and knowing what we're supposed to do whether I'm playing or not."
Milanovich said Toronto's offensive gameplan will change with Collaros at the helm. The 24-year-old is a much better runner than Ray and the Argos want to take advantage of that.
"A lot of the principles are still the same but we may move him around a bit more, we may ask him to do some quarterback runs which makes it more difficult for a defence to have to defend the run," Milanovich said. "His mobility is obviously a lot different than Ricky's and we'll do our best to take advantage of his strengths."
Many CFL teams are rotating quarterbacks in games this season to create on-field mismatches and throw opposing defences a curve. When Ray suffered a knee injury July 19 in a 35-19 road win over Winnipeg, Milanovich alternated both Collaros and Harris but isn't looking to do the same this time around.
"I won't say I will never do it but generally I like to give the ball to one guy and let him go,' Milanovich said. "Coming off the bench as a backup quarterback is one of the hardest things I think there is to do in sports because you don't get any reps and you're cold and then you're asked to go in and win a game.
"But that's what you're paid to do and I think Zach will embrace the fact he's going to get a full week of reps."