So where are the statements from Federer himself about his back injury, not opinions from clueless sports writers?
Federer had a back injury from early November '08 to about March '09. That's why he pulled out of Paris, Dubai, and the Davis Cup. He played a few events in between (Shanghai, Doha, and Aus Open) but he was never at 100%. No, he didn't mention his back injury prior to any of the events he played in because he didn't want to make any pre-emptive excuses in case he lost, like Nadal does with his knee injury announcements prior to major events.
That one writer is clueless because how could Federer have announced that he was suffering from mono DURING the Aus Open when he didn't know that the illness he had was mono until AFTER the Aus Open ended? But anyone with two eyes could see that he was sick with something during the AO. He even kept the mono secret from the public from when he found out in early Feb. to early March, but after he lost to Murray in his first match in Dubai, the press demanded an explanation because everyone could clearly see that his form was way off and that there was something really wrong with him.