All-Australian contender Mumford and 2005 premiership player Kennelly are nursing knee problems while Hannebery has a tight hamstring.
The Swans have named the trio in a 25-man squad to play the Blues at ANZ Stadium.
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"I expect all three of them to play. But obviously they have to train and we have make sure they get through training and we'll make some decisions after training," Roos said in Sydney on Friday.
"If any of them are sore and we still think they'll play we can wait because there is no hurry.
"But I expect that after training we'll have a pretty clear idea of what our team will look like."
Roos, who is stepping down at the end of the 2010 season, said Mumford had run on Thursday and he rated the former Geelong big man a "70-30" prospect.
"Indications are (Mumford) should be fine, but there's a difference between running and playing footy," Roos said.
"We'll test him out tonight. He won't do too much work and (we) hope that he is fine by Sunday."
Kennelly is a certain starter and Hannebery a 95 per cent chance, Roos added.
Sydney have a 7-1 win-loss record at the SCG in 2010 but have lost all three games at ANZ Stadium, the venue for Sunday's knockout final.
Swans midfielder Ryan O'Keefe recently made it very clear the players loved the SCG and would prefer to host finals at the cricket ground rather than the Olympic venue.
But Roos played down the issue on Friday.
"The home-town advantage is more about playing in your own state and the difference is getting on planes and doing all those sorts of things," he said.
"I heard someone call it a neutral venue. I've never been on a plane or travelled interstate to a `neutral venue' in my life."
The Swans have a 3-1 record in finals at ANZ Stadium and played one SCG final in the past decade, beating Geelong by three points in a semi-final in 2005.
