The 18-year-old will be Freo's sixth debutant this season and the 17th in the club's past 40 games.
Bollenhagen admitted feeling shocked when he found out that he would be playing.
"I was really pleased when I saw my name on the board, but I thought I was going to be an emergency again," he said.
"It was a nice surprise.
"I'm looking forward to playing this weekend and having a run with the boys."
Bollenhagen's first exposure to AFL level was during this year's pre-season when he played against Geelong in a NAB Challenge match, and he believes that experience will serve him well on Sunday.
"I discovered how fast the speed of the game is at this level," Bollenhagen said.
"I learnt how important composure is, and I learnt that I have to believe in myself and in my teammates."
The side has also been boosted by the inclusion of stars David Mundy and Chris Tarrant.
Rhys Palmer is out after he suffered a bruised shoulder in last weekend’s loss to the Western Bulldogs.
Clancee Pearce will also miss with a knee injury.
Mundy was a late withdrawal with illness last week, but his return will help strengthen a Fremantle midfield that was outplayed by a more experienced Dogs’ engine room.
Bradley had been in career-best form until a knee injury kept him out of the Bulldogs’ match.
He will help Aaron Sandilands battle Eagles’ ruck duo Dean Cox and Nic Naitanui.
Tarrant’s heel injury has forced him out of action since round 13.
His presence will solidify Freo’s defence, which has had talls Luke McPharlin, Antoni Grover and Alex Silvagni missing at various stages of the past two months.
Bollenhagen hails from South Australia and was the 52nd pick in the 2009 AFL Draft.
He has been playing for Perth in the WAFL this season.
Senior coach Mark Harvey said Bollenhagen’s football and physical strength has improved greatly over the course of the year.
“He is one of the youngest players that we have on the list,” Harvey said.
“He’s not there yet but it’s the way he has evolved. He shows really good poise and he is maturing.”
Fremantle assistant coach Chris Scott said Fremantle was not happy with its effort last week in conceding 158 points against the Dogs.
“We need to find improvement from multiple areas,” Scott said.
“We got smashed in and around the ball last week and gave up too many inside 50s. Then we couldn’t stop them once it got in there.”
Scott said this week’s inclusions should help the side win the ball in the midfield and be better defensively.
“We’ve hopefully got some experienced personnel back,” he said.
“David Mundy is going to be critical back in our midfield.”
On Sunday, Tarrant, McPharlin and Grover will play in the same side for the first time this season.
Scott said having McPharlin, Grover and Tarrant back in the same side would significantly boost Freo’s ability to stop the opposition from scoring.
“It has always been our preferred option to have the three of them in the same side,” he said.
“We think that all three are very versatile.
“Tarrant and Grover have shown that they can play on smaller forwards, and McPharlin is one of the best key defenders in the competition when he is up and going.”
Scott said the trio will add flexibility to Fremantle’s backline on Sunday and for the rest of the season.
“If West Coast goes tall, as they have done in the past, then we can cover them,” he said.
“But we also have the ability to cover the smaller players as well.
“If those three are playing well going forward, then that stiffens up our defence significantly.”
Scott wasn’t worried about the trio taking time to gel as a defensive unit, given they had not played much football together this year.
“They are all experienced players who have played in our defence and understand how we want our defence to work,” he said.
Fremantle has won its past six clashes against West Coast, including a win in round 6 this year.
The Eagles jumped to 23-point lead early in that match but Freo went on to score 11 unanswered goals on the way to a 38-point victory.
Sunday’s match will also be McPharlin’s 150th game for Fremantle, meaning he is eligible for life membership at the club.