"I want to lose weight so that I can make a difference on the pitch by getting back my agility and speed.
"I won't play for Flamengo unless I manage to lose weight because I want to earn my place and deserve it. I have always loved the club and the Maracana."
Ronnie also gave an update on his progress on the road to recovery.
"I have started to use a bike and I am swimming to ensure that I burn more calories than I eat.
"Last week I started an athletic nutrition programme where I don't drink coffee at breakfast and I have as many pieces of fruit and vegetables as I like.
"I think that I will be at my ideal weight within a month."