Olam barely made it five minutes through their 32-24 loss to the Sydney Roosters before he left the field clutching his arm after taking early contact.
The Roosters looked a class above the Storm's youngsters after their big guns entered the game for the second half, scoring two quick tries before digging in to seal the win after they'd conceded two against the run of play.
The Storm said they were certain Olam had fractured his forearm, although he'll head for X-rays to confirm the damage.
It's not what they needed with gun fullback Ryan Papenhuyzen already likely to be missing round one with a hamstring injury, although captain Christian Welch and centre Reimis Smith did make their return to the side.
Welch had just three runs in a limited stint on the field but found two offloads, while Smith was also quiet in his short outing.
The Roosters made sweeping changes for the second half, bringing on frontline stars Sam Walker, Victor Radley, Matt Lodge and Egan Butcher along with hooker Brandon Smith for his first run for his new club.
Smith looked fired up against his old side with a number of heavy hits and sharp dashes out of dummy-half, while he also contributed a try assist.
The hooker only played a small stint in the second half and admitted he'd need to build his gas tank when asked if he was ready to play 80 minutes at No.9.
"Not right now I don't, I was stuffed after 15 minutes," he told Fox Sports.
"I've still got plenty of room for improvement, I was a little bit shaky … still getting used to all the play names and I haven't trained the last three days.
"(Pre-season is about) what we've learned in pre-season and going out there and trying to execute it so we can take it into the real season.
"We were pretty poor tonight, we played against all their young fellas and they really gave it to us so we've got a lot of room for improvement."
Winger Jaxson Paulo also made an instant impact after joining from cross-town rivals South Sydney, scoring with a stylish try early in the second half.
Their depth options had impressed early and took an 18-12 lead to halftime, forward Elie El-Zakhem scoring an eye-catching try by busting three tackles before Tyler Moriarty and Will Fakatoumafi also crossed.
A length-of-the-field effort from Sua Fa'alogo was the Storm's best second-half moment, the young fullback catching the eye in a 205m, four tackle bust and three line-break display.
Tyran Wishart, Grant Anderson and Will Warbrick scored their other tries, while Sydney's Junior Pauga scored late to seal the win.
8°C