Coach John Longmire has been forced to undertake a major defensive shake-up this week after vice-captain Dane Rampe fractured his arm during an ill-fated morning run and utility Dan Robinson had surgery on the collarbone he broke in the 28-point loss to Port Adelaide.

They join a bulging casualty ward, which already includes the glandular fever-struck Isaac Heeney, ex-skipper Jarrad McVeigh and forward duo Gary Rohan and Tom Papley.

Heeney is hopeful of returning to full training next week, although he likely won't be considered for selection until at least round four. McVeigh is still a fortnight off, while Papley comes off the long-term injury list this week, and Rohan is due to do so in round four.

Aliir Aliir has overcome a pre-season toe injury and is fit enough for an AFL return. The original plan was to nurse him back to form through the reserves, but he now looks the logical choice to play centre half back against the Bulldogs.

Potential AFL debutants Lewis Melican and Nic Newman were strong in pre-season and are knocking on the door of the Swans' back six should Longmire opt to give Aliir one more week in the reserves.

Reid is also capable of switching to centre half back.

"I'm comfortable at either end," Reid said.

"That's something I've had to learn to do over the last few years, but something I'm open to now that I have that flexibility. If someone goes down back during the game or during the week, I'm able to flip.

"It's a really good opportunity against the Doggies. It opens the door with those guys being injured for guys to come in and have a really good impact.

"Last year I think we had eight or nine debutants and they all had a serious impact on how we went during the year so we'll look to that again."

Reid's convoluted journey to his 100th game has taken eight seasons, and the round-one clash against Port was his first at senior level since the qualifying final loss to Fremantle in 2015.

He was one of the best in a beaten brigade on the weekend, kicking three first-half goals and taking seven marks with Longmire singling the forward out as one of only a handful of Swans who won their individual battle across the ground.

The coach said Sydney lost too many 50-50s against the Power and Reid said rectifying that anomaly was the focus leading into the Bulldogs clash.

"We're pretty clear on where we need to improve and what we need to do to bounce back and have a better performance against the Dogs," Reid said.

"First thing is today at training, we narrow our focus a bit and make sure we're strong at that contested ball stuff. As John said, it just comes down to it on the day, those 50-50 contests you need to at least halve them at least not win them.

"Those 50-50 contests are so important, and never more important than when you're playing the Dogs."