After a false start to his international career in November, Johnnie has another chance in Scotland's final RBS 6 Nations Championship of the season to stake his long-term claims.
The 21-year-old made a try-scoring debut at international level in Scotland's victory over Romania in the autumn.
However the following week he suffered ankle ligament damage while playing against the Pacific Islanders, and that injury kept him out of action until just before the start of the Six Nations.
He was not able to prove his match fitness before the tournament began and the Glasgow youngster has endured a frustrating six weeks waiting for his chance, while Edinburgh's Dave Callam has been proving he also has the class to play at the highest level.
However, with head coach Frank Hadden ringing the changes for this weekend's trip to Paris, Johnnie is determined to reclaim his place near the top of Scotland's back-row pecking order.
"It's one chance and I've really just got to go for it. It is a huge game, but I'm hoping that I can rise to the occasion and prove to Frank what I can do," he said.
"The rest of the back-row boys have had the whole of the Six Nations championship, and they've taken their opportunities - this is my opportunity, and hopefully there will be more in the summer, so that I can nail down my place.
"In the autumn it was between Dave and myself, and I got the first shot - but then I got injured and Dave has come in and he has taken full advantage.
"So, now it is up to me to make the most of the chance I have been given.
"We're both of similar age and similar size, so it is up to us to use these games to prove that we can do a job at the World Cup.
"I think everyone feels they are playing for a World Cup squad place. Nobody is really antagonistic towards each other in the squad, but we are all really, really competitive.
"With Jason White coming back from injury in the summer, and Simon Taylor really coming onto his game at the moment, things just keep getting tougher and tougher in terms of competition for places - so this is a valuable opportunity to prove what I can do.
"I'm feeling match fit and I can't wait to get stuck in. I've not played much rugby in the last few months, and the games we have had with Glasgow have been in pretty horrible conditions, so there hasn't been much running rugby.
"However, the way Frank and the national team train is all about running, and we've done a fair bit of contact too, so there has been plenty of opportunity for me to get up to speed.
"There's nothing worse than sitting out injured and watching the rest of the guys out there playing.
"You just wish you could be out there on the field and making an impact."
There has never been any doubt that Johnnie is a classy performer on a nice day with the ball in hand, and he expects the conditions in France to be ideal for that style of rugby.
However, he is also hoping to prove that he can mix it if the match turns ugly or proves an attritional contest.
Johnnie observed: "Obviously France are going to be a physical side but you also know that they are always capable of the offload - but you've got to mix everything up, which is what I try to do.
"People can get caught up with the idea that a good player is the guy who is making all the breaks, but for me it's more important to get that turnover, or make that big hit, so that you get your team the ball back.
"I just can't wait to get in there and try to smash up what they are trying to do.
"I'm hungry and that's always an exciting thing for a back row going into a game."
Johnnie does not believe the Scots have anything to fear when they face France.
"We have to be targeting a win," he said.
"We can't be over-daunted by the fact that it is France in France and they are going for the championship.
"You have to remember that we didn't play well against Ireland and we didn't take our chances when they came but we still only lost by a point, so I think that shows we have the potential to upset the these supposedly bigger teams."