And midfielder-forward Leigh Adams, who had a left shoulder reconstruction last Friday, will now need medical treatment to repair his right shoulder, which was partially dislocated when Carlton skipper Chris Judd 'chicken wing' tackled him in round 16.
North football chief Donald McDonald said the Roos would decide whether Wells would play later this week.
'Because we play on Sunday, it enables us to give Daniel extra time to prove his fitness after missing last week," McDonald said.
"Obviously he is a vitally important player to us, so with that in mind it's crucial we don't rush him back. But if the medical staff say he’s right to go, then he will be out there for sure."
Wells injured his calf in the first quarter of North's round 20 win over Essendon and missed last round's win over Collingwood.
Grima and Adams (left shoulder dislocation) were also injured against Essendon.
McDonald said Grima was "tracking well in his recovery" and was expected to be available for North's round 23 clash against Greater Western Sydney.
North announced Adams' season was over last week.
McDonald said Adams' surgery last Friday had gone well, but he would now seek medical advice on the best treatment for his right shoulder.
"Leigh will visit the specialist later this week and a plan will be set out for him to have the right shoulder repaired at a later date," McDonald said.
"The good news for him is that he will be fully recovered come our camp in Utah in November and we expect him to be able to get a full pre-season under his belt with no restrictions whatsoever."
