The 34-year-old had long been known to be considering international retirement before confirming that the upcoming World Cup qualifiers against Macedonia and Belgium would be his last.
Although Coleman revealed that he was not told personally, the 43-year-old said that the news did not come as a shock to him.
"The first time I saw that was definite was when I read it in a newspaper," Coleman told reporters.
"He has hinted it would be his last campaign, so it's not a big surprise. In the back of my mind, I've been planning going forward, if I am going to be here, without Craig anyway.
"Craig has done numerous articles expressing what he thinks."
The Cardiff City forward has won 76 caps for his country.