Alex McLeish says Birmingham goalkeeper Ben Foster needed a break from international football to allow his body to recover fully from injury.
Foster has made himself temporarily unavailable for England after suffering from thigh, thumb and back problems this season, although he has been a near ever-present for Blues.
McLeish knows Foster did not take the decision lightly but explained it had been in the goalkeeper's thoughts for a while before making it public on Wednesday.
McLeish said: "You've got to respect the individual's decision. I chose to play for my country (Scotland) whenever they picked me. There was no retirement for me.
"It's not been an easy decision for Ben because he's thought about it for a long time.
"He did talk about it a wee while ago and I said, 'Think long and hard and don't make any rash decisions', but it's obviously still been troubling him.
"I think his body has taken a bit of a pounding over the last two or three years injury-wise."
McLeish said: "The England doctors, Fabio Capello and Franco Baldini have been excellent when we've dealt with them when he's pulled out of England squads.
"They could easily have said, 'What's going on?', because he's pulled out the last two or three, but he was genuinely having complaints.
"Some days he wasn't training here. Also when you go as a number two or three to the international set-up, you're normally doing a lot of practice shots for the (number one) goalkeeper.
"Again doing a lot of kicking was affecting his back because he already does a lot of kicking for us particularly with the amount of pass-backs he gets!"
McLeish stressed he would never put any pressure on a player to shun international football.
He said: "I would never ask a player not to play for his country.
"It's great for players to get recognition because it means that he's doing something right and hopefully the team's benefiting because of that.
"Ben's made a decision and, whether it's deemed that he'll get an opportunity to go back, I don't know because everybody will have their own opinion about it."