Vikings coach Denis Betts said the 22-year-old faces “four or five weeks” on the sidelines.
“That’s why you have a squad and we have Phelpsy [Cameron Phelps], Willie Isa and Chris Dean,” he added.
“It’s one of those things for Stef but he’ll be back.”
The injury to Marsh aside, Betts was pleased with the tough test from Workington as his side look forward to another Super League campaign.
“Workington have turned up and given it a good go and it took them to give us a blow on the nose for us to get going forward again. Our handling wasn’t great at times but these games are about knocking those cobwebs off,” he said.
“We got over the line four or five times and we didn’t get the ball down. If we had worked a little bit harder, then we could have scored a lot more tries. But we still created a lot of opportunities and scored 30 points.”
The Vikings first game of the Super League season is away to London Broncos on Sunday 3 February.
By Andy Jowett