AS one of the few midfield/forward types not either struggling with injury or suspended for Thursday night’s Europa League tie against Ajax, it came as something of a surprise to see Tom Rogic being allowed to roam freely around Celtic’s Lennoxtown training ground on Tuesday without the need for 24-hour supervision. It speaks volumes for Rogic’s renaissance this season – as much as it does about the length of the list of players likely to be unavailable to manager Ronny Deila – that if Celtic are to achieve the victory they need to keep alive their chances of making the knock-out phase, then they will surely need Rogic to be at his probing, creative best. And few would have predicted that just a few short months ago.

Rogic played just seven times for Celtic in season 2013/14 and not at all the year after. Plagued by a number of groin and ankle injuries, even a loan spell back home with Melbourne Victory would prove a frustrating experience. He returned from injury in March this year with a number of low-key appearances for the Celtic development side but, come the summer, there seemed a greater chance of Rogic being released than of him enjoying a second wind as a Celtic player. Deila, though, afforded him another opportunity and he has made the most of it. Still just 22 years old, the Australian has played 18 times already this season - many in his preferred No.10 role – and chipped in with five goals. It has been such an unlikely transformation in fortunes that even the player himself admitted he had wondered whether he would ever make it as a Celtic player.

“The manager came and spoke to me last season after I missed it all through injury,” he revealed. “We spoke during the season and when it came to the end we discussed my future and me coming back to training and playing a few reserve matches.

“I was back in full training and the manager said it would be a fresh start with no guarantees. So I came back on the same level playing field as everyone else, and he said that if I performed he would give me an opportunity. Luckily that proved to be the case.

“You never know what can happen in football. It can change so quickly. But was I completely sure I would come back here and get in the team? “No” is the answer. But that’s how it worked out and I’m really happy with that.

“It’s turned around for me and I’m just enjoying playing regular first-team football. I’m also fit and that’s been important. I’m not trying to prove myself to anyone but myself. Had I left without giving it a real crack because of injuries that wouldn’t have been ideal. But it’s in the past now and I want to keep on developing.”

Rogic, you sense, is not one for spending hours deep in contemplation about the road travelled so far. Asked, though, to pinpoint the moment he felt he was “back” as a Celtic player and he alights on the day he was handed his first start in almost two years.

“My first game back in a Celtic jersey, which was against Partick Thistle, was a great moment. I managed to score in the first half, which was a nice feeling and it was just something I wanted to do to kick-start the season.

“But I don’t think you can ever get comfortable. As I said, I’m always trying to get better. I hope I am at Celtic for years to come. I’m definitely settled here, I enjoy it, and the club were very supportive over the last 12 months. I feel good and believe I am in the right place to move forward.”

Celtic will take on Ajax with the equivalent of one hand tied behind their back. Nir Bitton and Stefan Johansen are both suspended and there are doubts over the fitness of Scott Brown and Kris Commons. It does not augur well for a match that may go a long way in deciding the long-term future of manager Deila but Rogic is not without hope.

“We’re missing a couple of big players but whoever plays on Thursday will be ready. We have a good squad. Obviously Ajax are also a good side. I thought we played well against them in Amsterdam and were in a situation in the match where we could have gone on and won it. It just wasn't to be that night. But I think that if we can perform to the levels we're capable of then we can certainly get the result we need."

Celtic, though, have leaked goals at a fairly alarming rate in Europe, conceding a minimum of two goals in each of their four Europa League matches this season. Rogic knows they must tighten up on Thursday. "It's obviously not been good,” he said, with some degree of understatement. “There have been sloppy mistakes individually which haven't helped. But we've been working hard to correct that. At the weekend we kept a clean sheet against Kilmarnock which was positive. We're now just looking to carry that into the match on Thursday."

The evening kick-off means an even bigger legion of Celtic fans will be tuning in back home. “In Australia it'll be a 7am kick-off so my family will just be waking up before watching it. The time difference can be a problem - some of the games are on at 2am for them - so it's not ideal. But they always watch when they can.”