Elsewhere, Richmond's mounting injury list has claimed another victim with prized youngster Sam Lalor sidelined with an Achilles issue.
Wardlaw was kept away from the rest of the Kangaroos players during the club's main training session on Thursday.
The gun midfielder has a "little sniffle" and is in some doubt for North's trip to GMHBA Stadium to face Geelong on Saturday.
Comben, who was a late withdrawal against GWS, has fully recovered and will slot straight back into the Roos' backline, replacing the omitted Toby Pink.
"We always err on the side of caution, knowing that they can do some isolated training away from the group and hopefully be good to go in 48 hours," North coach Alastair Clarkson said.
"It's mainly just protecting the rest of the group, so it doesn't rip through if it is contagious.
"If he deteriorates from here, then he'll be unlikely to play."
Competitive in tight losses against the Brisbane Lions and the Giants, North will be hoping they can cause a boilover and end the Cats' 10-year dominance of them.
Geelong have won their past 14 matches against the Kangaroos, North last winning at Kardinia Park in 2015.
On Thursday night, Richmond confirmed Lalor had suffered a "partial" Achilles injury at training ahead of the Tigers' clash with West Coast.
It is not clear yet how long the former No.1 draft pick will be sidelined for, with Lalor's setback extending Richmond's injury list to 16.
"We are disappointed for Sam, whose injury occurred during training on Thursday," Tigers football performance boss Tim Livingstone said.
"Sam is the consummate professional who will attack his rehab with the necessary care and commitment."
15°C