Clayton will rejoin former team-mate Nick Powell, who left the Alexandra Stadium for Manchester United in the summer, for the friendly against Germany U19s in Hamburg next month.
And Davis insists his selection is a reward for the striker's form this season, with Clayton making the starting line-up for the season opener against Notts County and featuring as a second half substitute in the two matches since.
"I am pleased for Max - we all are here. It is a great honour to represent your country and I don't want to stop him doing that. He enjoys playing for his country and rightly so," Davis told the club's official website.
"It is good for him to experience that. The going away and the different tactics. It is good for his education and unless he comes back to us with a serious injury then I am all for it. I am more than happy for him to be involved in games like that.
"It is a just reward for the form he has shown for our first team."