Jones guided the Exiles to promotion up to to Aviva Premiership in his first campaign in charge, but the club was relegated last weekend with a defeat to Northampton Saints.
"He has been excellent for the two years he has been with us, absolutely first class and I would say without prejudice that he is the best coach in the Premiership," Phillips told Sky Sports News.
"Obviously I hope we can hang on to him but equally I would respect his wishes if he felt it was now the time to move on. I hope he doesn't but we would respect him if does."
London Welsh continue their league campaign on Saturday with a trip to London Irish.