Johnson, 31, has struggled in recent weeks with leg problems, and missed Saturday's night's Hall of Fame Tribute Match at the MCG after being included in the extended squad of 30.
Cameron says Johnson would "probably" face the Dockers this Sunday, but might be one of a few to travel west early in order to allow his ageing body to settle after the long flight.
"He will probably be right to play. He trained today so hopefully he should be right," he said.
"With his age -- he's been struggling to get up in the past five or six weeks with his body.
"So in terms of the break, for him it was probably great."
Cameron also said "five or six players" could be considered for selection this week, following encouraging form in the VFL.
"Our Williamstown side played on the weekend and were fantastic -- Wade Skipper, Peter Street, Farren Ray, Tom Williams and Andrejs Everitt," he noted.
"We're in a great position because we've only got two injuries and there's a lot of players playing really well."
Cameron said the Bulldogs would discuss including an additional running player this weekend, to cope with the expanded dimensions of the Perth venue.
"We'll definitely talk about taking one, you always take an emergency over for that unknown, but you've definitely got to look at the wide and big ground at Subiaco," he said.
He also said there would be no underestimating Fremantle, despite the 1-6 start to the season it has assembled and patchy form displayed this year.
"We looked at the Freo-Melbourne game, and we looked at Freo-Geelong. Freo were fantastic in the first half and then they dropped off in the second half, but I think after fours rounds, everyone was saying Port Power was the best side at 0-4," he said.
"I think Freo are probably the second best side, because they quite easily could have beaten Geelong, and obviously Melbourne last week, and they pushed Hawthorn and Adelaide to two goals each.
"Other than probably their Richmond [effort], they could be 4-3."
He said the Dockers' most recent loss to Melbourne, from which they forfeited a 51-point lead, did not necessarily make them a more difficult outfit to come up against.
"It's a hard question because everyone says there's good times to get some sides because of the media coverage they've had, or when you're getting a side and you have less injuries," he said.
"At the end of the day, we can only do what we can do, and we've got to turn up to play like we played against Sydney. If we don't we'll get beaten."
Veteran midfielder Scott West is not expected to be available for another one to two weeks, as the seven-time best and fairest winner continues to nurse a sore knee.
"He's got some bone stress, and hopefully he'll be playing the Kangaroos the week after, or Hawthorn down in Tassie after that."
