not that I agree one way or the other, but I can absolutely understand why Agassi would skip the AO and played a small tournament a week later.
First, it wasn't a week, considering the preparation time for the AO and the 2 weeks during the AO, it is more than 1 month of lead time.
Plus, even assuming Agassi was about 80% healthy before AO, he might not want to work so hard and risking the injury again just to get to the 2nd or 3rd round of AO and then lose at the beginning of the second week due to not being 100% to begin with.
The season is 10-11 month long and AO is in January. It is totally understandable that taking care of his health issue is in his best interest. Playing the small tournament was just simply a better channel to test how fit he was at the time, rather than in a Grand Slam.