Anderson has claimed knee injuries were responsible for derailing his Manchester United career after he completed his move to Internacional.
The 26-year-old Brazilian midfielder joined his hometown club on Tuesday after several years of frustration at Old Trafford, with United allowing him to move for free despite paying 26 million pounds for his signature in 2007.
Anderson was a first-team regular for the first four years of his stay at United, but then fell out of favour with questions over his weight and commitment -- and he spent last season on loan at Serie A side Fiorentina.
Now he is hoping for a fresh start back in Porto Alegre.
In comments reported by the Guardian, Anderson said: "I played for eight years for Manchester. I would like to thank the club. In my first four years I won everything there -- Champions League, Premier League and (the Club World Cup). I had a knee injury and returned to play again too fast. I played but the knees were not equal and I got myself injured again.''
Anderson suffered several knee injuries while at United, most notably in February 2010 when he hurt his anterior cruciate ligament, ending his season.
He also faced questions regarding his weight and commitment.
Asked about that, he said: "Do you think I'm not fit? A player will always be criticised. I had injuries in the past, but I have to be quiet right now and answer in the field.
"It will be a pleasure play for a club such as Internacional. I want to be happy as I was at other clubs. I'm coming back to Porto Alegre because Inter went after me. The president gave me attention. I was training [at United] but not playing.''