As someone who has missed out on an Irish World Cup squad himself, Mike McCarthy is well placed to comment on how Devin Toner is feeling right now.
It is no secret that he is a big Toner fan seeing as he had a t-shirt with "The Real Dev" hanging up behind him when he was on Monday's OTB AM.
The former Leinster lock said he could tell how disappointed Toner was after failing to make the World Cup squad.
"It will be a massive knockback, I text Dev the other night and got a response.
"Just from the text I received from him, I could tell how down he was about it. This is something Dev hasn't really had to deal with in his amazing career," McCarthy said.
He thinks with the pedigree he has with this Irish team, it was an unusual omission from Joe Schmidt.
"You know we've heard all the stats, 50 games under Joe Schmidt and 67 caps for Ireland. It's been 10 years that Joe has known him and more than anything it's just a surprise to everyone.
"Joe usually gets quite frustrated with how the media pick up on a team early on in the week before a match. This is one that no one saw coming.
"It's more shock than anything really and it is tough to bounce back from it," the former Leinster player admitted.
McCarthy has been in Toner's shoes before, missing out on the 2011 World Cup squad. He does think that Toner has the temperament to get over the disappointment.
"I did all the training in 2011 and didn't get on the plane so that was a tough blow.
"Dev will keep fit and he will keep working hard and he has got a great mindset.
"Dev will go back to the province and go back to their schedule there and their training system," he said.
Even for those who knew they would not be going to Japan for a while, it is a tough pill to swallow, according to McCarthy.
"It will be tough watching and even for the likes of Dan Leavy who is in a completely different scenario.
"He is injured and can't be out there it's incredibly tough and you can just picture what the guys are doing in camp," he said.