In a sign of the club's depth, their two 2023 grand final wingers - Cobbo and Jesse Arthars - have both been named on the extended bench for Wynnum Manly and Burleigh as those sides prepare for their respective Queensland Cup semi-finals.
If Cobbo plays, it will be his first game back since tearing a hamstring in round 23.
Between them, the Broncos' back five ran for over 1000m against Canberra in the 29-28 qualifying final win on Sunday.
It would be a huge call for coach Michael Maguire to make changes for Sunday week's preliminary final against Canterbury or Penrith, but Cobbo is a proven match winner.
Mariner has been in and out of the side this year but since round 22 he has been a regular. His return has coincided with six wins out of seven. On a personal front he has scored six tries and made seven line breaks in a rich vein of form.
"It has definitely been not an ideal season but I have learned a lot and taken so much from going back to Q Cup," Mariner said.
"I took first grade for granted. It is hard to play first grade but staying there and being consistent is another thing. I am taking it week by week and trying to get better.
"Sometimes I used to rely on a lot of talent but I learned from what Madge (Maguire) is putting us through that it is a lot of hard work and a lot of extras on and off the field.
"Those are the things I cleaned up and the things I have been focusing on."
The 22-year-old has walked the talk since rejoining the side after a stint with Burleigh. His fellow outside backs are also doing the business, as was evidenced against the Raiders where they took the pressure off the forwards.Â
"That's definitely something we've been building towards. We know how much work our big boys get through," Mariner said.
"The least we can do is get us out of our own end and I was very happy with the back five. We stepped up and helped the forwards. That's definitely our standard now."
Mariner was unsure whether he would get his position back but now just wants to keep it.
"The way the team is going you never know what is going to happen, but I was always ready for an opportunity and I just didn't want to take it for granted," he said.
As for Cobbo, Mariner said the Dolphins-bound outside back had done a great job getting himself ready to play again.
"He is a massive part of this squad and has been working real hard on his rehab to get himself back. Good on him for getting fit," Mariner said.
"Everyone would love to play but he is more focused on himself. He knows what he needs to do."