Over the weekend Charlton's manager mentioned that the club hadn't treated Young's ankle ligament damage properly a few years ago, but they had since learned from their mistakes.
It transpires that Young, who suffered the same problem again at West Ham last week, wasn't given an injection through concern he would react badly to one.
Curbs said: "When he had this injury before we waited a long while before giving him an injection, but he responded well to it."
Ahead of the club's FA Cup sixth round replay at Middlesbrough on Wednesday, Curbishley also expanded on comments he made in the press conference before last weekend's 0-0 draw against Everton.
He said: "I was asked at a press conference was Richard Murray thinking about a replacement if I left? And I said ‘well, I think he is because he has got to'. I left it at that. I have got no power over what people write. I spoke to Richard, and he is quite happy with what I said."
Everton manager David Moyes pointed out after the game that although a point was undesirable for a potential push for a European spot next season, it was an important game for his side because it prevented Charlton going above the Toffees in the table with five games to go.
Source: The Sun