Wolves completed the signing of the Scottish international in a £6.5million deal on Thursday.
McCarthy has been tracking Fletcher since the forward was at Hibernian.
“We were looking at him when he as at Hibs and I came to watch him,” he told Sky Sports News.
“We actually got our business done early last year when Burnley signed him and I thought fair play and I was interested to see how he would do.
“They did well to sign him but sadly they have gone down.”
