Johnson singled out one of the Blues' young players for acclaim, and thinks it would not be a surprise to see them playing Champions League football next season.
"Tammy Abraham has impressed me the most because the Premier League is a totally different beast to the Championship," he told Betdaq. "To score the amount of goals he has so far shows he's handled the change very well.
"I hope Chelsea can fight for a top four place.
"If they can get anywhere near then it's an absolutely fantastic season for them. With Manchester City and Tottenham not firing on all cylinders I think they have got a real chance."