The Three Lions boss may have a nice guy persona, yet he has not shied away from making bold decisions, whether it be easing out all-time top scorer Wayne Rooney or going for promise over experience.
Cahill looked set to be on the wrong end of one of those calls after a lack of game-time at Chelsea saw him left out of the squad for March’s friendlies against Holland and Italy.
Chris Smalling and Michael Keane were other big-name absentees, but – unlike those two – the Chelsea captain worked his way back and earned a place in Southgate’s 23 bound for Russia.
“No, I didn’t (think his chances were gone),” Cahill said of March’s setback. “I felt it had took a knock missing out on that squad, especially the last squad just before you meet up. It was kind of a big squad to miss out on.
“So I realise that maybe it took a little knock and I really had to dig deep to try and perform from there to the end of the season to get myself back in the frame.
“That’s the way it has worked. Of course last time I was disappointed. There was a lot going on at that moment of time and I missed the squad, but I never didn’t have the belief that I could make the squad.”
It did, though, mark quite a change in fortunes for Cahill.
Just a year on from captaining Southgate’s England in Germany, the 32-year-old was watching from afar – and wondering whether it would be the same come the World Cup.
“(The manager) spoke to me before he left me out,” Cahill said. “Obviously that will stay between me and him, but I respected him a lot for that phone call because I’d sooner find out from the horse’s mouth than anywhere else.
“That’s exactly what I said to him that I respected the fact he’d called me. I said, ‘That’s football’. At that moment in time there was a lot going on, and he left me out of the squad.
“But there were no hard feelings about that, no problems. It was about working hard to get back in and I managed to do that.”
Cahill achieved that by digging deep and focusing on regaining his place in the Chelsea starting line-up, eventually going onto end the season in style by lifting the FA Cup.
It was in the build-up to the final that the Blues’ captain anxiously waited for news about the World Cup squad, only to miss Southgate’s call when it eventually came as he was driving to training.
“I thought potentially it could be bad news,” Cahill said, “because in my experience of being involved with England for seven or eight years you usually don’t get the call, you just receive the information that you’re going to meet up and what times etc.
“So to get the call a different way, I’d be lying if I said I wasn’t a little bit nervous when I was listening to it (the voicemail), but I was delighted to be involved in another tournament for my country.”
Boasting 58 caps, Cahill is comfortably the most experienced member of the travelling party – and one of just five survivors from the squad that floundered at the World Cup in Brazil four years ago.
“I think about personally, in my career, one thing that’s missing, is a tournament where I feel that we’ve had a real good crack and a real good run at,” Cahill said.
“It’s something personally that’s missing. These boys have got many, many years ahead I’m sure.
“But again, you shouldn’t look (at it) like that, you should look like it’s your last one because you never know what’s round the corner.
“I just want to try to enjoy this tournament. Enjoy means go as far we possibly can. Enjoy means by winning games. And that’s the only way you enjoy.”
Tammy Abraham has stressed the importance of possession as England Under-21s prepare for their second game of the Toulon Tournament.
Aidy Boothroyd’s side toiled in their opening match against China, particularly in the first half as China led at the break. However, England finally got to grips with the hot conditions and second-half goals from Dael Fry and Abraham, who struck in the 89th minute, sealed a 2-1 win.
England play Mexico in Salon today and Abraham expects an improved performance from the holders.
“It was tough against China they were a good team and when we conceded a goal we had to stay focused,” said the Chelsea striker.
“We knew if we kept moving the ball around we would get chances. It’s hot here and you seem to lose breath quite easily so it’s important to keep hold of the ball so we don’t get tired and keep moving it fast to try to tire the other team.”