That has led to calls for Dallaglio to return from some quarters, even if, at 34, the Wasps number eight's impact may not be what it was in his prime.
Dallaglio, himself a former England captain, has not featured for his country for over a year, and Johnson is concerned at the effect his recall could have on the rest of the squad.
He told The Times: "Can he do a job for England? Yes, but can he do it at the highest level against the best teams?
"That's something Ashton needs to discuss with him.
"He has to ask himself: 'Do I need a guy like that on the bench, or in the squad, will he be a strong influence?'
"And how does it affect the squad bringing an old guy back and saying that he is better than them?"
Johnson does, however, admit that England's forwards need to toughen up if they are to challenge the southern hemisphere's superpowers in this year's World Cup - where they face the granite-tough South Africans in the group stages.
In particular, the former Leicester man wants to see England tighten up around the breakdown, where they have been overpowered at times since his retirement.
He added: "It always used to be our strength.
"But now we get bullied at the breakdown."