The Italian press had suggested that the troubled forward would be shipped out, however Ranieri insisted he simply needs to get himself back in shape.
"Adriano has only recently returned due to bureaucratic problems and he needs a few more training sessions," said Ranieri.
"He played two good games (before Christmas) but now he needs time to get back into an acceptable shape.
"I expect more from him during the rest of the championship but also from (forwards Francesco) Totti, (Mirko) Vucinic and (Jeremy) Menez."
Adriano has often suffered from weight and motivational problems in recent years and when he signed for Roma at the start of the season he was visibly overweight.
Having worked throughout pre-season and the first half of the season to get nearer his ideal fighting weight, he seems to have let himself go again on holiday in Brazil.
However, he is not the only player to take extended leave as injured midfielder David Pizarro has yet to return from Chile.
"Pizarro is recovering in Chile, he's an important player for us and remains part of our project," added Ranieri.
"I'm not disappointed with his behaviour and I hope that he's back fit again soon, I repeat, he's an important player for me.
"I spoke to him and I have to believe in what we discussed and not in what has been
"He's part of my project and I would only let him leave if he asked me to."
Fifth-placed Roma host Catania on Thursday as they look to close their seven-point gap to leaders AC Milan.