The Dutchman has been sidelined with a calf injury for two months, but only now has he revealed how the injury was sustained.
"It was bad - I am lucky to be alive," Agustien he told the Western Mail.
"I was back home in Holland and driving my car but for no reason it slipped and hit a ditch. The car went into a cornfield and flipped over a couple of times.
"It went over twice so my head was pretty shaken up. The car was gone - I was so lucky it was only a calf tear.
"And I've been saying my prayers ever since. I thank God every day anyway but I had my angel with me when it happened.
"It could have been worse but it is in the past now and I want to concentrate on my future and to be ready when I get my chance with the team."
Agustien is hoping he can make his return to action this weekend against Newcastle and he may get his chance with Ki Sung-yueng injured.
"I am hoping to start at Newcastle," he said.
"I've been working hard, making sure if I get chance to get on the pitch I am ready to show what I can do.
"I had five minutes at a difficult time at Southampton but I think I did well in the position I played and in the small amount of time, so hopefully that can help.
"Everybody knows what my qualities are and I think I should be playing - that's my opinion and everybody would say that about themselves. But I think I should be playing so I need to let my feet speak for me.
"Because when you get an opportunity you have to make an impact because there are lot of midfield players here and a lot of midfield players who are doing well.
"Of course I want to play but Swansea is not about me. There are a full squad of players who want to play and perhaps think they should play. All I can do is work hard and if I get that chance then take it. That's what we all have to do, I'm no different. If it comes on Saturday then great, if not then I will keep working hard."