The midfielder said that after having suffered six knee injuries and the same number of surgeries, it was prudent to focus exclusively on his club career
The midfielder has spoken for the first time on his Ghana snub after he sent a statement to the west African FA revealing that he could no longer combine both club and national duties due to health reasons.
"When I was at Borussia Dortmund, I could divide myself [between club and country]," he told Vanity Fair.
"But with AC Milan, between the Italian league, the Champions League and the Coppa Italia, I am no more able to do this.”
The 24-year-old said his knee injury worsens whenever he has had to board flights and that has contributed to his decision to quit national duty.
"My knee has suffered six injuries and six surgeries. It gives me pain on flights due to pressure changes.
"So I have to say goodbye to Ghana because I am keen on my health," he added.
The former Portsmouth player shocked Ghanaian fans when he decided to hang up his international boots on November 4. He switched nationality to Ghana a few months before the 2010 World Cup in South Africa.
He has won nine caps with Ghana and scored a goal in the Round of 16 game against the USA at the global showpiece.