Cottagers boss Martin Jol was without his two main strikers Johnson and Zamora for the 1-1 Boxing Day draw at Chelsea due to respective groin and Achilles problems and neither are set to recover in time for the game at Carrow Road this weekend.
Therefore Clint Dempsey will be pushed further forward, while Bryan Ruiz is also in line to face the Canaries after the pair combined for Fulham's goal on Monday.
Winger Duff is also missing due to injury, while fellow midfielder Simon Davies is hopeful of a return for the New Year fixtures but continues to miss out due to a back problem.
Fulham are also without defender Zdenek Grygera and goalkeeper Mark Schwarzer with long-term knee and spine problems respectively.
Meanwhile, defender Stephen Kelly was delighted with the side's response to the 5-0 defeat against Manchester United when they secured a draw at Chelsea and he wants a further improvement on Saturday.
"We were very happy on Monday because we needed to give a good result to the fans," Kelly told the club's official website. "To go to Stamford Bridge is never easy but to come away with a draw is a great boost and shows us what we're capable of.
"I thought we got forward well and defended well against Chelsea. We were resilient and at times we showed glimpses of really good attacking football. The manager set up the team that put the onus on them rather than us sitting back.
"We caused Chelsea a lot of problems and that's what the intent was and it worked out well. Everybody was very happy with the performance and hopefully we can build on that when we go to Norwich on Saturday."