Swallow is unlikely to be risked for what would be his first AFL game of the season, although Wells (foot) will be given until the 11th hour to prove his fitness.
Swallow made an encouraging comeback from an Achilles injury when he gathered 23 touches in three quarters in North Ballarat's VFL loss to Geelong at Simonds Stadium last Sunday.
The skipper trained at Arden Street on Thursday, but coach Brad Scott isn't inclined to rush him back to AFL level before next round's bye – especially after the Roos' strong 4-2 start to the season.
"He's a chance and it's really tempting – he'll train today – but I would think we'll err on the side of caution with Andrew," Scott said.
"I'm really confident that he could get out and perform well and not be at any risk of getting injured, but the prudent thing to do would be to give him another full game in the VFL and get him back somewhere close to his best.
"As great as the temptation is to try and get him in before the bye, we'll probably go with pretty close to the 22 that got the job done over in Perth (against Fremantle) – with the exception of Scotty Thompson coming back in (from suspension)."
Wells was on crutches on Monday, and the gifted midfielder was again missing from training on Thursday.
"He's in a different situation – he's only missed a couple of games and he's really fit – so with 'Wellsy' will give him right up until the last minute to prove his availability," Scott said.
"But again, I can guarantee you if he's playing he'll be 100 per cent, because if he's any less than that it's not fair to 'Wellsy', it's not fair to the team and we'll be playing guys who are fit and ready to play."
On Sunday, North will be aiming to become the first Victorian team to win the week after travelling to play in Perth.
The Western Bulldogs, Essendon and St Kilda have all suffered defeats following the trying trip, although Gold Coast and Port Adelaide both won after their matches at Patersons Stadium.
"The playing group and the leaders are really determined to get the job done this week and they've said themselves that we feel that if we don't get the job done this week last week will count for nothing," Scott said.
"So I think you will see a pretty determined group this week."
North suffered its first loss to Gold Coast in round 11 last year, going down by 15 points in the wet at Metricon Stadium.
Gary Ablett dominated with 33 touches and two goals, but Scott said the Roos couldn't afford to be too Ablett-centric in their focus on Sunday.
"I think if you start thinking too much about Gary you forget about (Jaeger) O'Meara and (David) Swallow and (Dion) Prestia and (Michael) Rischitelli," Scott said.
"They're building a really good midfield now, so I think they'll back their midfield against ours. We'll largely have to do the same and not focus too much on one player."
