The 22-year-old injured his left knee in a third-quarter centre bounce contest in the Suns' 43-point win over North Melbourne, hobbling from the field and heading straight down the race.
Early reports suggested Nicholls had injured his posterior cruciate ligament – a typical ruckman's injury – but Suns coach Guy McKenna was less specific after the game.
"It's a knee, clearly. He's on crutches at the moment but I know that's more of a medical procedure and concern," McKenna said.
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"We'll wait to see how that settles. The bye's certainly going to be handy but we'll have to wait to see.
"He'll get scans on Monday and we'll assess the damage, hopefully as little as it possibly is, on Monday."
If Nicholls has a lengthy stint on the sidelines the Suns' tall stocks are relatively thin.
Developing ruckman Daniel Gorringe has recently gone in for Achilles surgery and will miss up to a month, while Zac Smith may be available after the club's bye next week.
But Smith is likely to return via the NEAFL to build up the necessary match conditioning after his return from a ruptured anterior cruciate ligament in round eight last season.
That means the Suns may need to throw together a makeshift ruck department in the meantime.
"We've certainly got some limited tall options but we've got some options," McKenna said.
"We've seen Rory Thompson go into the ruck, Sam Day went into the ruck today, Charlie's (Dixon) back.
"It's not ideal, we've run out of a few that's for sure."
Twitter: @AFL_BenGuthrie
"We'll wait to see how that settles. The bye's certainly going to be handy but we'll have to wait to see.
"He'll get scans on Monday and we'll assess the damage, hopefully as little as it possibly is, on Monday."
If Nicholls has a lengthy stint on the sidelines the Suns' tall stocks are relatively thin.
Developing ruckman Daniel Gorringe has recently gone in for Achilles surgery and will miss up to a month, while Zac Smith may be available after the club's bye next week.
But Smith is likely to return via the NEAFL to build up the necessary match conditioning after his return from a ruptured anterior cruciate ligament in round eight last season.
That means the Suns may need to throw together a makeshift ruck department in the meantime.
"We've certainly got some limited tall options but we've got some options," McKenna said.
"We've seen Rory Thompson go into the ruck, Sam Day went into the ruck today, Charlie's (Dixon) back.
"It's not ideal, we've run out of a few that's for sure."
Twitter: @AFL_BenGuthrie
