McKay is on a two-year contract with Doncaster to bring in players and sell them on.
"In every squad there are two or three good players who aren't getting a game for whatever reason. We will take them to Doncaster, put them in the shop window and sell them on with sell-on fees. Mahamadou Diarra has a c.v. with Monaco, Real Madrid and Lyon on it. I've told him if he comes to Doncaster he will be with us for six months before he's playing in the Premier League.
"He was on 4.7m net at Real Madrid, but he'll be playing for £2,000 a week if he comes to us."
McKay lives 20 minutes from the club and his 14-year-old twins are promising players at the academy, given a chance to make the grade with Rovers.
He has a healthy relationship with new boss Saunders, who started with two wins but saw his team lose 3-0 at home to Leeds last Friday.
"I'm doing this to prove it can be done and I've been honest enough to admit I'm only here for the money. I don't need the £100 and I probably won't even invoice for it."