Mam had a staring performance in last week's opening trial with feeder club the Wynnum Manly Seagulls and will have the chance one again to show what he can bring to the team from the start of the season, with the 19-year-old in his first season on a top 30 deal after impressing at the Souths Logan Magpies last year.
All four players have been named in Brisbane's side to play the Gold Coast in the Broncos' trial on Saturday evening, with Walters confirming in the pre game to Fox Sports that no decision has been made yet, and that all four will play 40 minutes. Kelly and Walters have been named to start, with Gamble and Mam to presumably play the second half.
"Not as yet," Walters said when quizzed on whether a decision had been made.
"That'll be done over the next two weeks. We have a trial next week up in Mackay against the Cowboys.
"Tonight we are splitting the halves, and they are all getting 40 minutes each. They can show us what they have got tonight and then next week we will move on from there and see who will partner Adam.
"At this stage it's still an open race. All the different candidates have got different qualities that they bring."
Walters also confirmed that Reynolds himself will be involved in the selection process to pick his new halves partner.
The former Rabbitoh is a star recruit for the season ahead and has been made club captain for 2022.
"We will sit down after our second trial. I'll sit down with Adam and a few other guys and we will make the selection there," Walters said.
"I'm expecting the individuals to put their hand up over the next few weeks, have a crack and go after that position."
Walters confirmed during the week that Mam was in consideration for the position alongside the other three more experienced halves, with the coach saying "if he is old enough, he is good enough."
Adam Reynolds also indicated Mam was the player who has impressed him most during the pre-season.
The Broncos and Titans kick-off at 8pm (AEDT).