With little more than four weeks until the side is named for game one of the series in Adelaide on May 31, Brisbane's Reece Walsh and the Dolphins' Hamiso Tabuai-Fidow are looking to keep the heat on incumbent Maroons No.1 Kalyn Ponga.
After seven rounds Walsh had eight try assists, five line breaks and four tries.
Over the same period, Tabuai-Fidow, known as 'Hammer', had notched two try assists, four line breaks and eight tries.
"They have been brilliant and both have done a great job for their clubs," Slater told AAP, who also highlighted the work being done by AJ Brimson at the Titans.
"It is a tough one for them - I know that position better than any other on the field.
"I can see their growth areas in the fundamentals of the position and not just in the highlights we see regularly that get us out of our seats, which is great."
Slater was impressed with the way Tabuai-Fidow handled a challenging 2022 at North Queensland and has kicked on under Wayne Bennett this year.
"He had a tough 12 months," Slater said of the Dolphins player.
"He had the No.1 jersey for the Cowboys in the first month of footy last year.
"Then he gets injured and Scott Drinkwater never gave it back. That's the way footy goes sometimes.
"He got an opportunity to go to the Dolphins under Wayne and he's really grown as a player."
The Queensland coach said Brisbane's Walsh has shown his willingness to get in front of attackers and put himself where he needs to be as he works on the defensive side of his game.
"With Reece, when you are talking about defensive plays as a fullback, he is putting his body on the line and being courageous," Slater said.
"He is starting to get himself into good positions defensively as well and when you get that part of your game sorted you can help your team get in really good positions defensively.
"I see growth in both those players in that area."
Ahead of Friday night's clash with Parramatta in Darwin, Broncos coach Kevin Walters said Walsh had made a strong case for State of Origin selection.
"He'd be in my Queensland team but I'm not the coach so that's up to Billy Slater and the selectors," the former Maroons mentor said.
"He's progressing really well for us, Walshy, and all the work he's been doing is terrific.
"He's got to maintain that, and (then) all the rep teams and the pathway will look after itself.
"He's a real footy-head, studies the game … he's always thinking about footy."
