The South Korean suffered a hamstring injury in the north London derby defeat to Arsenal and missed two games as well as his country’s friendly with Japan last week.
But he returned to full training on Friday and will be involved in the north-east.
“Son is good. He will be selected,” Mourinho said. “He was injured, he trained with the team fully for the first time this morning.
“Yesterday he was coming to do partial exercises, not a complete session, this morning was the first day he did it. Last week he didn’t train at all so it was completely impossible to play international.
“This time was a good chance for him to recover.”
Newcastle are battling for survival in the Premier League and Steve Bruce will be hoping to see a big reaction following the heavy defeat to Brighton & Hove Albion prior to the international break.