Roberts, 18 has been on trial with the Mariners for several weeks, and impressed with a hat-trick against North Shore Mariners in preseason that caught the eye.

Roberts has spent time with both Melbourne City and Western Sydney Wanderers in the past, but said that this opportunity with the Mariners feels like a second chance and a new start for him.

“For me, and for my family, this is really big,” Roberts said tonight. “It was tough since I left Western Sydney, trying to figure out where I was going to be.

“Staj gave me a chance to come here and play and train at the Mariners, it’s not something I’m going to take lightly and I feel like I owe Staj and the club so I will try to reward them now.”

Roberts was born in Guinea after his parents fled violence in Sierra Leone, and made his way to Australia before he was 10 years old.

This year, he returned to NPL club Mt. Druitt to restore his confidence and get some game time, and believes it was a key to him arriving where he is now.

“I think I needed to take that step backwards to then take another one forwards,” he said.

“From now it is about working hard, giving 110% every time and hopefully getting some game time in the first team.”

Mariners Head Coach Alen Stajcic said it was an exciting opportunity for Roberts and a further indication of the Mariners providing opportunities for young players.

“John has been on trial now with the Mariners for a few weeks and he has impressed us with his work rate, his footballing ability and also his attitude around the club,” Stajcic said.

“He’s a hard worker and this is a big chance for him to show us what we know he can be, given his time formerly in the Joey’s and also as a Young Socceroo.

“This news follows on from Lewis [Miller] signing and Sammy Silvera and shows the Mariners are a club that is ready to provide opportunities to our talented young players.”

Meanwhile Adelaide United have signed Chinese footballer Yongbin Chen.

The 20-year-old attacking midfielder joins the Reds from Qingdao Red Lions and will arrive in Australia shortly subject to his visa clearance.

 “We are very happy to finalise our squad with the addition of Yongbin Chen," Adelaide United Chairman Piet van der Pol.

“During our scouting processes, we had looked at a couple of other possible signings, however decided upon Chen as we believe he is one of the most promising young talents at Qingdao Red Lions.

“At 20 years of age, Chen is an offensive midfielder who has a lot of potential and we are excited to contribute to his development at Adelaide United.

“This is consistent with our approach to developing youth talent and we hope to continue this in the future.”