My message to them is to remember they have everything to gain and nothing to lose.
Back in 2003, before the World Cup in Australia, I was nowhere near the Wales team. In fact I hadn’t even been part of the squad for more than two years.
After a whirlwind 2000 when I made my Test debut aged 22, under Graham Henry, I slipped out of the Wales frame almost as quickly as I had arrived and I took that far too personally.
But I got myself together and had a really good season with Neath. I knew I was doing well, I was playing with confidence and scoring tries. I thought at the time, if I can’t get myself back into the squad on this form, then I never will.
But it was still a surprise when Steve Hansen, who hadn’t paid me any attention up until that point, called me up for the third of Wales’ warm-up matches in the summer of 2003 against Romania in Wrexham.
I had been forced to watch the Six Nations games on the TV in sheer frustration so by the time kick-off came at the Racecourse Ground, I was chomping at the bit.
I knew this was probably my one and only chance – albeit a very slim one – to get on that plane to Australia and I was going to make sure I made the most of it.
But I can honestly say I wasn’t nervous. There was no pressure on my shoulders because I figured I had nothing to lose.
So I went out there, played with a smile on my face and expressed myself in the only way I knew how. As it worked out, I scored two tries and people were talking me up.
I figured a game against Romania was unlikely to be enough to get me in the World Cup squad and there were some really good wings around like Dafydd James, Gareth Thomas, Rhys Williams and Mark Jones, who were all ahead of me.
But at least I came off the pitch pretty pleased that I had done the best I could and had left selection in the hands of the coach.
Then a few days later I was told I was in the squad and I was going to Australia to play in the World Cup. It was an unbelievable moment.
Of course the joke was that I was actually named as a third scrum-half behind Dwayne Peel and Gareth Cooper, two guys who would go on to tour with the Lions two years later.
But I just giggled whenever that was mentioned because I didn’t care how I got back into the squad, I was there.
That is the message all 47 players in Gatland’s current training squad.
They may have been on the fringes so far, or even may yet to have played international rugby, but they have to remember they are in the squad for a reason and it’s up to them to play their way into the final squad.
I’ve only seen Ross Moriarty a few times but I liked what I saw. He offers something Wales haven’t had in recent years. There’s a touch of the old-fashioned flanker about him. He’s abrasive like his father was and is a strong ball-carrier.
Eli Walker deserves a shot after such bad luck with injuries. He has speed and great rugby instincts but he just needs that one game for Wales for him to kick-on and fulfil his potential as a star of the future.
Hallam Amos is an option at full-back, with doubts over Liam Williams. He is strong and great finisher but I want to see him get involved in the game far more than he does for the Dragons.
Of course there is also a warning to the senior guys not to switch off. As well as those ‘bolters’ who come into the squad at short notice, there are also plenty of examples of established players being overtaken – or simply playing themselves out of the squad.
Dafydd James missed out in 2003, Gavin Henson and Brent Cockbain in 2007 and Dwayne Peel in 2011.
Sometimes it’s complacency, other times it’s form or simply not fitting in with the coach. But now you’re here, don’t let the chance pass you bye to play at a World Cup.