Manly are confident Dylan Walker hasn't done any structural damage to his knee but will wait for the swelling to subside before sending him for scans.
Walker went down early in the second half of the Sea Eagles' win over Penrith on Saturday with the star centre being carried from the field.
"We think he just got a little bit of contact to the knee," Manly high performance manager Dan Ferris said.
"He's just got a bit of swelling. All his ligaments are fine, we've checked them and they are all good.
"Swollen up a little now so he'll just have to get some scans on Monday."
Manly have the bye next round and officials are confident he'll be fit for the grudge match against Melbourne at Lottoland the following week.
Winger Matthew Wright is also expected to be fit and available after he injured the A/C joint in his shoulder scoring a try for the Sea Eagles at Panthers Stadium.
The positive prognosis comes at a welcome time for Manly, who lost winger Jorge Taufua to a hamstring strain before Saturday's win.
Manly have now already used 29 players in 2018, about two players more than they used for the whole of last season.
Despite that though, they've pulled off upsets on high flyers Penrith, Melbourne and Brisbane but were still 14th on the ladder before this round.
"I think it says a lot," Barrett said.
"I know when we're all healthy and we've got our best players on the park we can trouble most teams.
"It's finding the consistency with what we're doing but also the continuity within the group. It's not just game day, it's during the week.
"I was watching a Paul McGregor interview and he was saying they had a clunky performance (against Parramatta). They still won but it was the most disrupted week they've had all year.
"We've pretty well had 16 weeks of that, so it makes a difference."