So when a mystery number popped up a few times on his phone one week at work, the 23-year-old gave it no thought.

Luckily, the apprentice electrician called back on the Saturday and found out it was a Central Coast Mariners official asking him to come in for a trial.

Thomas heads to Mariners training on Wednesday and Thursday this week keen to get more time to push his case for a contract.

"Crazily enough, I finished my electrical apprenticeship about six or seven weeks ago, and literally a week after, they gave me a call and said we've been looking at you for a while and we're pretty keen to get you in," Thomas said.

"It was a massive surprise, I was buzzing.

"At the start I've got to go down for a couple of days and more or less try to impress them.

"Obviously they know how I play because they've watched my games but it's just seeing if I get along with the A-League regime, if I can keep up with the tempo and that sort of stuff.

"My foot's in the door as it sits and I've just got to beat everyone out that's trying to take the position."

Thomas has become one of the best centre-backs in the NPL Northern NSW over the past six seasons.

After breaking through at Weston in 2017, Thomas has since been part of Maitland's rise to powerhouse status, but he admitted he had given up on a shot at a higher level.

"It's not the age thing really," he said. "Me and one of my best mates, Jimmy Thompson, who plays at Maitland with me, we speak about this stuff a lot, and when we play at the level we have been for as long as we have and not get a call, it's like, it's not going to happen.

"We accept it for what it is, and then to get that phone call, it's like wow. That's where it was kind of unexpected."

Now he's going all in for his chance, quitting work to focus on football.

"Obviously the opportunity was there and it took a lot of people around me to say, look, stop being an idiot and go for it," he said.

"I had a good career going being an electrician, which I do enjoy, but I was like, screw it, let's go for it ... I'm giving myself the time and attention this deserves to have a good crack at it."

Thomas, who grew up at Kilaben Bay but now lives in Merewether, played briefly at the Mariners, in under 16s then again in under 20s.

He serves the second game of a two-match ban when second-placed Maitland (33 points) are away to leaders Broadmeadow (35) on Saturday in crucial premiership clash. Thomas copped two yellows in the 1-1 draw with Charlestown, giving him a second red for the season.