Vlaar has fought his way back from career-threatening knee problems which kept him out for a season each time.
But he said: "I'm never afraid of getting injuries, especially from my knee. I didn't play for two years and then I came back.
"There were some moments in the training back then where I felt it was not good and the problem was not totally gone when it should have been.
"But it is much better now. I am much more confident with it and I don't worry about it any more or let it change the way I play."