Rossi, 27, made his first Serie A appearance in four months on Tuesday, coming off the bench to score in Fiorentina's 4-3 loss to Sassuolo.
The unlucky striker has suffered multiple knee injuries in the past three years, but pulled up well after his return.
Rossi said he needed to prove to Italy coach Cesare Prandelli that he was fit enough to play a role in Brazil.
"I need to play to go, but I need to show I am in good physical shape and that I am capable of helping the team," he told a news conference on Wednesday.
"I am thinking about it, but there are still a lot of things to do with the Viola. We need to tie up fourth place and then finish the season well against Torino in front of our own fans.
"I'm not fearing anything, I'm just sorry that I wasn't able to continue after four fantastic months.
"But fear has never come into it, my desire to get back to playing well out on the pitch has always been stronger than any fear."
With two league matches remaining, Fiorentina are well-placed to finish fourth in Serie A and claim a place in next season's UEFA Europa League.
Rossi is eyeing the remaining games against Livorno and Torino as an opportunity, and said Vincenzo Montella's men had been unlucky with injuries and suspensions this season.
"I am ready to play on Sunday and against Torino. My knee is fine, though of course there is always room for improvement," he said.
"I think that the team we have now is strong. This year we have been unlucky, with Mario Gomez's injury and also Borja Valero's four-match suspension.
"I am proud of this team and of what it has achieved. We have two matches to play and we need to finish the season in the best possible way."
