Lee was stretchered off in the 78th minute of South Korea's 1-0 win over Oman in Canberra on Saturday with the Bolton Wanderers midfielder having come off second best, following a lunging tackle by Abdul Salam Al Mukhaini.
After the match South Korea's coach Uli Stielike had played down concerns about Lee but subsequent scans have revealed the 26-year-old is likely to miss three weeks, which would ensure he plays no further part in the tournament.
"Yes, he has a fracture in his right leg," a spokesman for the KFA told Perform.
"But it's not serious, it's a hairline fracture."
While the spokesman insisted the Stielike and South Korea's medical staff have yet to make a final decision on Lee, he did concede that it would be "impossible" for the winger to play a part against Kuwait on Tuesday.
With the final of the Asian Cup to be played on January 31 - exactly three weeks after Lee sustained his injury - there is a slight possibility he could play again in the continental championships if South Korea went that far, but the KFA are also considering sending the Bolton man home.
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