Ballantyne had been in some doubt after sustaining a shoulder subluxation in last week’s win over Melbourne.
Freo made two changes for the clash against the eighth-placed Power, one forced after ruckman Aaron Sandilands hurt his cheekbone against the Demons.
Young tall Jack Hannath comes into the team, as does hard running midfielder Cam Sutcliffe.
Defender Alex Silvagni was omitted and has been named as an emergency with Hayden Crozier and Jesse Crichton.
Fremantle general manager of football Chris Bond said the club was confident Ballantyne would play.
“He’s got through training well this week and he’s been given the okay by the doctors,” he said.
Bond said Freo was confident Hannath would come in and play a role on Saturday.
“He’s played 10 games this year and we’ve been really pleased when he’s been able to come into the team and then he’s gone back and been able to play at Peel,” Bond said.
Bond said Sutcliffe’s running attributes could be important against a hard-running Port outfit.
“He’s very versatile, he’s been able to play in the midfield, and he’s been able to play back and forward as well,” he said.
“He’s got some really big strengths to his game and we’re going to need that against Port Adelaide.”
The football manager said the club had full confidence in Zac Clarke to lead the ruck in Sandilands’ absence.
“Zac’s had a really good year for us and he’s continuing to improve, and with Jack (Hannath) coming in as well, we think they can work really well together.”