The 22-year-old has had his career curtailed by a serious groin injury and only now does he have the chance to impress Celtic management.
The Australian has only made five starts, and 15 appearances in total, since joining in January 2013, spending six months on loan with Melbourne Victory in the first half of last year.
Now he is determined to put the past behind him and earn a place in Ronny Deila's midfield.
"It was a bit of a nightmare," Rogic said. "I don't want to get into it too much. I had a serious groin injury. I feel I've come out the other side of that.
"It was a pretty testing time. I never thought it would be as long as it was.
"It's hard to put into words, it was pretty difficult. But that's past me now. I just want to be positive and look to the future."
Rogic impressed in Celtic's 2-0 win over Den Bosch in a midweek practice match and started again for its 5-3 defeat by Dukla Prague on Saturday despite the return of nine players who had been given extra time off because of international duty.
"It's good to get games," Rogic said. "I'm just happy to be out there. It's enjoyable and I just want to build on it. I'm feeling really good.
"There are a lot of good players but I will do everything I can."
Rogic will use the experience of Nir Bitton as inspiration - the Israel midfielder became a key player last season after taking time to adapt to the Scottish game.
"We came to the club at similar times," Rogic said.
"Nir had a bit of a slow start and proved with a run of games what a quality player he is. So of course I take confidence from that."
Celtic was well beaten by the Czech side at St Mirren Park but Rogic feels the team can quickly improve ahead of the Champions League qualifiers.
"They made it tough for us but we were too open and we need to be better," Rogic said.
"It's only the second game of pre-season and for most of the lads starting it was their first.
"There is always going to be a bit of rust so I don't think it's anything too serious to worry about."
