Brown conceded six goals to Sydney Swans powerhouse Kurt Tippett last week while swingman Ben Reid was playing up forward.
However, Sidebottom said on Thursday he was confident Brown and Keeffe could do the job against Franklin, who is expected to be named in Hawthorn's side after missing one match with a sore hamstring.
The Hawks' two-time All Australian has booted 50 goals in 12 games against the Magpies, who are one-and-a-half wins outside the top four and the vital double chance with three rounds remaining.
"He usually kicks goals against us so our defenders will have their work cut out," Sidebottom said.
"I'm sure we've got the guys who can control him."
Jarryd Roughead (59 goals) poses another major threat to Collingwood's defence.
Asked if Reid would be parachuted back into defence to do the job on Franklin, Sidebottom said: "No, probably not."
A former All Australian defender, Reid kicked two goals in Collingwood's upset win over the Swans, and Sidebottom says his 2010 premiership teammate will stay in his new role for the moment.
"We've got Keeffey and Browny down there," Sidebottom said. "(One of them) will go to (Franklin)."
The 22-year old says a top-four finish would be a big boost for Collingwood's premiership aspirations.
"In the last three weeks we've just pretty much got to worry about what we can control," he said.
The Magpies are aiming to knock off three top-eight rivals in three weeks after accounting for Essendon and Sydney, with Sidebottom tallying 30 disposals and a goal against the Bombers and 23 touches and two goals against the Swans.
"We've played against the best teams and in the last two weeks we've shown that we can match it.
"I suppose my form has been a little bit like the team. It has been a little bit up and down," Sidebottom admitted.
"We want to be playing our best footy at the end of the season, and likewise myself."
