"She was pretty tight for the first two days but she has slowly loosened up and now I am running freely, doing my weights normally so it has loosened up really well. "It feels 100 per cent now."
If he is picked, Dagg will have some other things to worry about - like the pitch at Millennium Stadium in Cardiff. He had heard about the vagaries of the surface but never played there.
Traction looked as though it could be an issue but, if he was picked, he would use the captain's run the day before the test to choose the length of his sprigs wisely.
Wales have bigger things to worry about after five consecutive defeats.
Foster was unsure how Wales coach Warren Gatland would be dealing with his current team crises and was more concerned with the All Blacks rather than opposition issues.
"He will respond like any other coach, try to fix it."
Clearly Wales had not gone as well as they wanted against Argentina and Samoa but that only highlighted how prepared teams had to be for every test they played.
"We have talked about us building through this tour and making sure we prepare well because, if you don't prepare well, if you don't do Sunday to Friday well, then you can get bitten on Saturday," Foster said.
Matches against Scotland and Italy were about getting everyone in the touring squad involved and managing their workloads at the end of the season.
The other aim was to continue the development and build combinations.
"We have done some really good things," Foster said.
The All Blacks had responded to a variety of unexpected challenges. Some got them flustered at patches but they had been able to nut out a solution to those issues.
"It is going to be really important this week because, while there have been some questions about their (Wales) recent run of form, their eye is on this game.
"We know there will be plenty of heat coming at us and we are going to have to figure our way through that. Quite frankly, that has been the biggest lesson for us, how to learn through a game."
The All Blacks setpiece was strong, their defence and reaction to some phase play had to be tightened while there were a range of smaller areas to keep fixing.
The changing tempo in tests, players finding themselves in situations they were not used to - these are the issues the All Blacks have to confront.