Shami has not played for the national team since the 50-overs World Cup final against Australia last year and was close to full fitness before being ruled out of the three-test series against New Zealand that begins on Wednesday.
"To be honest, right now it's pretty difficult for us to take a call on him. Whether he would be fit for this series or the Australia series," Rohit told reporters.
"He recently had a setback. He had a swelling in his knee, which was quite unusual... We're keeping our fingers crossed.
"We want him to be 100% fit more than anything else. We don't want to bring an undercooked Shami to Australia. That's not going to be the right decision for us."
India head to Australia for five tests beginning on November 22nd and Rohit said he was hopeful about Shami's participation.
"The physios, the trainers and the doctors have set a roadmap for Shami. He's supposed to play a couple of games before he plays an international match," Rohit said.
"We'll see where he's at after this New Zealand series and then take a call at what stage of the Australia tour he will be fit for us."
Rohit said he was looking forward to the challenge of facing New Zealand after a 2-0 sweep in the Bangladesh series.
Another series victory will be India's 19th on the trot since a 2-1 defeat by England in 2012.
"For us, each team brings different challenges. We've played a lot of cricket against New Zealand, we know their players as well as their strengths and weaknesses," Rohit added.
"But I've said this many times, what's important for us is that what we do better in this series than we did in the last.
"We'll try not to focus too much on the opposition. We'll try to focus more on ourselves."
