The 26-year-old missed three games earlier in the campaign to play for the country at the Asian Games - helping South Korea to a victory which earned him exemption from military service.
Though Son will miss South Korea's opening two group matches in the United Arab Emirates, he will join up after the Premier League visit of Manchester United on January 13.
If Paulo Bento's side reach February's final Son could miss as many as four matches of Spurs' season, including the Premier League games against Fulham, Watford and Newcastle as well as the Carabao Cup semi-final second leg against Chelsea.
And with the north Londoners attempting to mount a title challenge alongside Liverpool and Manchester City, Son has lamented the timing of his latest international call-up.
"Of course I feel very sorry because I miss already in September [Asian Games]," he said.
"I feel sorry for my team-mates, the fans and the coaching staff.
"It's difficult. Sometimes you think it's a bit sad, but it is also important for my country.
"I hope I can keep my form for the national team and when I come back here again as well."
Since returning from the Asian Games, Son has recaptured some of his best form with eight goals and five assists in his 16 top-flight appearances.
The ex-Hamburg and Bayer Leverkusen forward admits he was jaded following his exploits for his country but is ready to rise to the big occasion once again.
"I was tired after the Asian Games because in that tournament it was playing after [every] two or three days," he added.
"It is very important to be right mentally at the Asian Cup and to come back with a strong mind and be strong physically.
"It [November] was a turning point for me because I was tired and I didn't travel.
"It was good to have this time, some days off, and hard sessions with the team. But the Asian Cup is big for us because we have not won it for 59 years.
"I'm going there not just to enjoy it, I am going there to win something and come back with confidence."