Jimmy O'Brien is a great recent example of how there's never a good time to lose your place in the queue.
Back in December, the Leinster utility back would have been considered first choice in the right wing for his province, and next cab off the rank for Ireland in the event that one of Mack Hansen or James Lowe was unavailable.
Indeed, back in January when news came in that Hansen would miss the Guinness Six Nations due to a dislocated shoulder, it was assumed that the Kildare man would step into the 14 shirt for the championship, having impressed off the bench for Ireland at the World Cup in October.
That assumption lasted roughly two hours, with Leinster confirming the 27-year-old had suffered a neck injury, which would rule him out indefinitely.
O'Brien spent just over four-and-a-half months rehabbing his neck injury, returning off the bench in the Champions Cup semi-final win over Northampton Saints, before starting Saturday's BKT URC win against the Ospreys, scoring a try and being named player of the match in the 61-14 victory.
His performance on the left wing gives Leo Cullen food for thought ahead of the Champions Cup final, as well as Andy Farrell for this summer's tour of South Africa.
The trouble for O'Brien is that while he was laid up, others were making hay.
Jordan Larmour (above) has wrestled possession of O'Brien's usual 14 jersey with Leinster, and a hat-trick on Saturday means he's not likely to give that up any time soon. From a national point of view, Calvin Nash fitted seamlessly into the Irish starting team.
Cullen has insisted that he's keeping an open mind around selection for the meeting with Toulouse in just under two weeks time, and O'Brien's versatility means he is in with a shout of being involved at the Tottenham Hotspur Stadium.
Before that, the province must navigate another big URC game, away to Ulster on Saturday evening, and O'Brien is desperate to get one more chance to impress.
"To be honest I just want to play as much as I can at the moment," he said after Saturday's 47-point win at the RDS.
"That's the one thing I’m missing, game time. I’ve no issue, I’d love to play next weekend.
"Selection for the Champions Cup final is going to be tough, there are so many good players, you see the lads still injured at the moment, there are so many players stepping into their position and playing well at the moment so it’s such a tough team to get into.
"No doubt if I get selected next week and play well, hopefully we can turn the page to the Champions Cup final after that. Next weekend is huge for us at Ulster."
That neck injury was the first major injury for a player whose career had been steadily progressing since 2020, averaging 19 games across each of the last three seasons.
"It was frustrating, luckily before that I hadn't really got any serious injuries so I think you have to take it as something that comes with the game; everyone gets hurt," he said.
"I'm friends with a couple of lads who had injuries, long spells on the sidelines and they've all come back and hit the ground running.
"It was frustrating to miss out on European games, the Six Nations and stuff like that definitely.
"It was frustrating but you can't really do anything, there's a timeline and you're focused on trying to get back and, when you get back, try put your hand up for selection and try and play well."
"With the neck I knew it was going to be long term and I wasn't certain when I would be back. It's all dependent on scans.
"So, it was frustrating because with a hamstring you know it's six weeks or something like that and you have a deadline. Whereas this one, I was kind of waiting and waiting for scans to be positive.
"It definitely took a little bit longer than I was hoping, but I'm just delighted to be back."
While his layoff was long, he was still able to stay involved with elements of training and preparation, which has helped him get up to speed with the defensive plans Jacques Nienaber has introduced.
"Luckily with my injury I was actually able to train a good bit. I was training for maybe four weeks, non contact," he added.
"I was able to talk to Jacques [Nienaber] and talk to the lads, ask about the system we play in. You stay very involved even when you're injured, I was chatting to Jordo [Larmour] and Lowey [Lowe], the lads playing on the wing and 13s, 15s, Frawls [Ciarán Frawley] and Hugo [Keenan], we all help each other.
"It is definitely a different system. It’s good, everyone’s nailed on it now, and we have it down,"
Before Leinster can start thinking about Toulouse, they must first get by Ulster at Kingspan Stadium next Saturday.
Saturday's win leaves Leinster second in the URC table with two games to play, one point back from leaders Glasgow.
And with the top seed in the URC guaranteeing home advantage all the way to a potential final, O'Brien says they won't be resting up for this weekend's trip to Belfast.
He said: "Away in Ulster is always tough. I've played a couple of games up in Ravenhill. It’s obviously a good atmosphere, but pretty hostile against you when you’re up there. It’s always good to play in, but it’s a tough place to go.
"We’re not going into next week and thinking about Toulouse. It’s always taking it week-by-week.
"Whoever is selected now this week to play against Ulster will be 100% focused on that and putting in a good performance because again we talked about it.
"Good teams can back it up and play well in those games. They’re not going to look ahead. Everyone has back up and everyone will be trying to put their hands up for selection. You can’t take a game off and have a bad game."
Watch highlights of all the weekend's action on Against the Head, 8pm, RTÉ2 and RTÉ Player
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