Canterbury's Origin prop Dylan Napa is joining teammate Kieran Foran on the sidelines after suffering the same serious ankle injury in his team's tight loss to Melbourne.
The early diagnosis on the Queensland forward is sydnesmosis, or a high ankle sprain, although Napa didn't believe it would require surgery as Foran has undergone.
He left AAMI Park on Sunday afternoon in a moon boot, with further scans scheduled for Monday back in Sydney.
"I'll have a scan to confirm the injury and reassess from there," Napa said.
"I don't think it's nearly as bad as Kieran's but fingers crossed as he's out for three months, so hopefully I can be back within a few weeks."
The 26-year-old, who has been in impressive form since joining the club this season, hurt the joint in the very first set while tackling Storm lock Dale Finucane.
He bravely attempted to play on but realised he was becoming a liability for his team.
"I was thinking about Kieran and how he played the whole game so I was feeling like a bit of a cat going off but I was becoming a liability in defence and I could hear the Storm saying, 'Get at Napa' and I didn't want to let the team down."
Bulldogs coach Dean Pay said losing Napa early was a big blow for his team, which really counted in the back end as the Storm roared into the lead.
"He's an Origin player and you take an Origin player out of a game ... I think he played something like 60 minutes last week so that's a big loss.
"I was so proud of the boys who picked up the slack for the rest of the game."
Australian Associated Press