Jonathan Joseph has revealed that he played in England's World Cup games against Australia and Uruguay with only one third of his chest muscle still attached to the bone.
The Bath centre's return from surgery against Northampton last weekend was a full month ahead of schedule and he makes his second club appearance of the season in Sunday's Champions Cup clash with Wasps at the Ricoh Arena.
Joseph's pectoral muscle was torn during the World Cup opener against Fiji and he was subsequently ruled out of the pivotal showdown with Wales, resulting in a panicked overhaul of England's midfield.
He appeared to heal quickly and started against Australia before stepping off the bench for Uruguay. It was only when the injury was then scanned upon his return to the Recreation Ground that the extent of the damage was understood.
"I felt something in my pec and wasn't too happy about it as I'd done the other pec before and it felt a little bit similar," Joseph said.
"I did rehab on it, missed Wales and then hit all my targets lifting in the gym. I did everything needed as far as reaction work was concerned, strapped it and managed to play against Australia and Uruguay with no dramas.
"When I got back to Bath, they had a little play with it. I had felt something in there during the Uruguay week but wasn't too concerned.
"Bath had it scanned and in fact I only had about a third of the muscle still attached.
"Although I could feel it against Australia and Uruguay, it wasn't too bad. I was aware of it, it was strapped but I managed to tackle all right.
"It was a World Cup and I was going to do everything I could to play. Obviously, I wasn't aware that there was only one third attached."
Joseph's return had been pencilled in for mid-January, placing his participation in England's RBS 6 Nations opener against Scotland in doubt, but now he has up to eight games to prove he is still the nation's finest outside centre.
Competition for the number 13 jersey has increased with Elliot Daly's dynamic start to the season at Wasps and will only grow more intense in January when Manu Tuilagi's long-term groin injury has fully healed.
Adding to the sense that Joseph is having to prove himself all over again despite this year's fireworks is that in Eddie Jones there is a new England head coach to impress.
"It's important for everyone to put a marker down. Obviously, the World Cup wasn't great," Joseph said.
"It's a clean slate with a new coach, so I'm glad to be playing a lot earlier than expected and to put my best foot forward.
"I'm not too concerned about what other players are doing. All I'm concerned about is making sure I am doing all I can to be where I want to be.
"I can't be getting distracted by what other individuals are doing in other teams. I am solely going to concentrate on myself as that is all I can control."