The Eels hosted an open training session on Monday with approximately 5000 fans in attendance at their base in Kellyville, with the club preparing for their first grand final since 2009, when they lost to the Melbourne Storm.
The Storm were ultimately docked of that premiership in the fallout from the dramatic salary cap scandal, which was uncovered during 2010, however, it didn't bring the premiership to Parramatta as the club seek to end what is the longest ongoing drought in the competition.
Opacic missed Friday night's winning preliminary final effort over the North Queensland Cowboys with a hamstring injury that he sustained the week before as Parramatta blew the Canberra Raiders off the park in the semi-finals.
He revealed to AAP during the club's open media session that he was close to playing last week.
"I felt like I was pretty close (to playing the Cowboys) but it was probably just too much of a high risk to take the field.
"I just thought, there's more risk in playing and hurting myself and missing this game (the grand final) and letting the team down."
Opacic said however that he would have to improve further to play.
“I daresay I’d have to run fully on Wednesday or by the main session on Friday. It’s all about running at high speed and under fatigue," he said.
"It's in the hands of the medical staff but if I'm not 100 per cent ready to go, I'm not going to jeopardise the team for my own benefit," he said.
"If I go out there and go down in the first 10 minutes, the boys are down a player for 70 minutes. That's not fair on anyone.
"The boys have worked too hard for this.
"But in saying that, (playing in a grand final) is an absolute dream come true and I don't want to miss it for anything."
It's understood Opacic will be named on Tuesday afternoon, while Bailey Simonsson, who replaced him last week, will remain on standby.