Tiger Woods and golf go hand in hand with Americans. While it isn't a hugely followed game, practically everyone knows who Tiger Woods is and what sport he plays. One of the biggest golfing events is being held and he's not going to be present. As one of the top players of the game, it's a bit shocking to say the least.
I think it would only be odd if he pulled out for a reason other then injury. Considering he is currently recuperating from surgery I think it is perfectly normal that he wouldn't want to participate and risk another injury. Normally he has scheduled surgeries around the majors, but this must have been one that could not have waited.
No, it is not strange that Tiger Woods will not be at Augusta this year, because that man is past his prime. He used to be on top of the world, but he threw it all away by choosing to cheat on his wife and become a public laughing stock. I am glad that he is no longer performing well.
Lets face it, Tiger Woods lived his 15 minutes. I do not think it is strange that he will be absent from Augusta this year. His performance has been lack luster for years and it is unlikely that is going to change. While he experienced a lot of wins in the beginning, I would say he is on par with what is more common in the golf world and there's nothing strange about that.