Newly recruited Worcester midfielder Ben Te'o has missed Monday's England training session due to muscle fatigue.
The Six Nations champions are currently touring Australia where they will face the Wallabies in a three-Test match series during the June internationals.
Te'o, who recently as 2014 converted from league to union, signed with the Premiership side from Leinster ahead of the 2016/17 season.
The 29-year-old New Zealand-born centre will be competing with Luther Burrell and Owen Farrell for the number 12 jersey.
The former Leinster player was on sidelines and subsequently missed a very crucial training session, on Monday, as Eddie Jones' troops prepare for the first Test against Australia in Brisbane on Saturday.
England defence coach Paul Gustard has confirmed that it Te'o sat out Monday's training based on the medical staff's recommendation that his muscles needs a rest, but will however be part of the full training on Tuesday.
"It was on the advice of the medical department," Gustard the Belfast Telegraph.
"He's all good and has settled in really well. He's a good character and gives us something different, adding to our attacking options."
Given his physical prowess, both on attack and defence, and ability to fend off defenders with ease, Gustard is pleased with the manner in which Te'o has adapted since switching codes.
"He's a big, physical guy. He has the intent to hit people, knock them back and dominate that gainline, control the gainline, the momentum and pace of the ball," Gustard said.
"That's in his DNA and he has that physical intent that most defence coaches like.
"On top of that he's pretty savvy. He's used to playing a channel-based defence in rugby league for the last 10 years of his career. He went to Leinster and learnt different way of defending, so is adept at both systems."