Redknapp said: "It will be difficult if Roy goes.
"English managers are not easy to find. There are not too many getting an opportunity at top clubs.
"For me the two brightest managers in the Premier League are both on Merseyside, Brendan Rodgers and Roberto Martinez.
"Brendan has done an amazing job at Liverpool. They were great to watch.
"I liked the way they played and scored goals, were an attacking team. And Martinez he is fantastic.
"Wigan got relegated but they beat Man City in the cup final and some of the football they played at times was fantastic and at Everton they have been excellent as well.
"The way they get their teams playing passing and movement they produce in their teams is fantastic.
"I think that is the way forward for us to play that way in the future.
"One is from Northern Ireland and one is Spanish but maybe they will want to manage England one day."
For the big stories and the banter follow us on Twitter: @tribalfootball