Finkler, who leads the competition in assists, ruptured his anterior cruciate ligament in the 2-1 loss at Western Sydney Wanderers on Tuesday night and will require a knee construction, sidelining him for eight months.
Often the beneficiary of Finkler's lead-up work, Rojas said the Brazilian had been key to the Victory's climb into the top four on the A-League ladder.
"Finkler's injury is a huge blow for us," said 21-year-old winger Rojas ahead of Saturday's clash with Wellington Phoenix.
"He's created a lot of goals and been key to our attacking plays."
Rojas said Isaka Cernak, Jimmy Jeggo or Billy Celeski could all step in.
"We've got quite a few that can slot in. I'm comfortable one of them can come in and do the job."
The loss of Finkler will intensify coach Ange Postecoglou's search for a signing this month.
Pint-sized Kiwi international Rojas is off contract in April and a likely target for overseas clubs who could come knocking in this month's tranfer window but he was keen to see out the season with the Victory.
"Of course I want to stay," he said.
"I've started the season and I want to be here at the end."