The Cats demonstrated their premiership credentials with a 19-point win over Hawthorn on Easter Monday, and they did it without a number of first-choice players, including Steven Motlop and Allen Christensen.
"We're not that healthy," Selwood said at Simonds Stadium on Monday morning during the launch of a new program to encourage people in Geelong to quit smoking.
"We've still got an injury list that's quite deep at the moment, so we'll gradually get those players back.
"Motlop played on the weekend … so we're getting there, and we think we'll be a different side come the end of the year."
Having been sidelined by off-season knee surgery, Motlop returned via the VFL on Saturday night.
He kicked one goal and gathered 14 disposals, although the fitness staff limited his game-time.
Motlop is likely to spend another week in the VFL before being considered for Geelong's round seven clash with Richmond at the MCG.
"I think he's pretty keen to play against Port Adelaide (this weekend)," Selwood said.
"But that's up to the coaches and the medical staff."
Christensen, who is recovering from back surgery, won't return to the field until the second half of the season.
However he is already doing plenty of running and could be seen striding out strongly at Simonds Stadium on Monday.
The weekend's results, which saw Port Adelaide jump above Hawthorn into second place on the ladder, mean the Cats are preparing for a top-two clash for the second week running.
And Sunday's twilight game at Adelaide Oval will be Geelong's first visit to the redeveloped stadium.
"We seem to be (playing top sides) weekly at the moment," Selwood said.
"West Coast were up the top, then the Hawks. It's a challenge. We're going over to Adelaide and we look forward to that.
"They're a really good side and coached really well, so they're going to be a hard side to beat."
There are doubts over the fitness of defender Andrew Mackie, who suffered hamstring tightness in round four and was then subbed out of the win over Hawthorn at three-quarter time.
But Selwood was unsure about Mackie's condition.
"I haven't seen him this morning, and I haven't spoken to the doctors," he said.
The Cats' depth continues to be one of their greatest weapons, with a number of mature-age recruits and youngsters standing up strongly against the Hawks.
"I think it's really important for the guys who've come to the footy club in the last few years: Hamish McIntosh, Jared Rivers, and then you add in George Burbury and Jordan Murdoch on top of that," Selwood said.
"It's just a really important win for those sorts of guys. And we do understand these wins early are really important for the back end of the year."
