https://twitter.com/frontrowbrian/status/157364924786548737
Link is Japanese but FightOpinion has been credible. 
lmfao @ FRB twitter source
You can't be serious.
It says he started training on Wednesday and will be fighting the Brazilian in March.
Hi frb!
Last time I saw Arona he was so fat, I'm not even saying chubby .
Not true. Arona just denied it to Tatame magazine (in portuguese: http://www.tatame.com.br/2012/01/12/Arona-nega-rumores-de-luta-em-Sao-Paulo).
Basicly he said: "I was contacted by several events in Japan, USA and even Brazil, but didn't sign anything. I didn't even talk with them. My goal is to fight again in the middle of the year, because now I'm just worried about building my Training Center".
"I'll choose the best offer when the time comes. For me, it would be better to be in the international scene, because my goal is to fight in the UFC, but fighting in Brazil is also great".