Eddie Jones has ignited a club versus country row by telling Bath owner Bruce Craig that he is unqualified to criticise his methods during England training sessions.
Ben Te'o is the latest player to be hurt after the powerful Worcester centre aggravated a thigh problem first sustained in the NatWest 6 Nations when performing a weights session last week, rendering him unable to tour South Africa next month.
It raises the number of casualties sustained during England camps under Jones to 15 with five of those incurred by Bath players.
Craig has declared that the quantity of injuries is "totally unacceptable" and stated "there has got to be significant questions asked about duty of care", adding "what is going on in the camp?".
England's head coach returned fire on Wednesday by insisting his methods are necessary to prepare a team for the international arena.
"I don't have any concerns. We train appropriately for Test match rugby," Jones told Sky Sports.
"The only reason I'd alter it is if we need to train harder, or we need to train lighter, to be at our best for Test matches.
"We prepare players for Test matches. I don't think anyone at a club has the right to tell a coach how to train a Test team."
Jones added on BBC Radio 5 Live: "I haven't seen any figures to suggest the number of injuries are unacceptable.
"No-one on our staff has suggested they are, but Bruce is obviously an expert in training-ground injuries, so I'll have to be subservient to his greater knowledge."
Te'o, who was set to start at outside centre in the series opener at Ellis Park on June 9, must undergo surgery but should be fit for the start of next season.
"Benny was tight after a weights session - during the weights session when he was doing a lift he felt some tightness about his knee," Jones said.
"He was scanned and it showed he had an old tear from the Six Nations game against France, and therefore it was too big a risk to take him on tour.
"The injury is one of those corks and when you've got a cork you've always got damage to the muscle. Sometimes they repair and sometimes they don't. He'll be back for the start of the season."