ST KILDA has suffered a significant blow to its hopes of retaining its top-eight position, with key defender Dougal Howard set to undergo surgery after fracturing his wrist over the weekend.

Howard hurt his wrist in the opening quarter of St Kilda's victory over North Melbourne last weekend, with scans subsequently revealing a fractured left scaphoid that will require surgery on Thursday.

The Saints have so far been apprehensive to rule Howard out for the remainder of the season, given there are five games to play before finals, but haven't yet put a timeline on his return.

It's another blow for Ross Lyon's side, which is limping towards the finals and will also be without Bradley Hill (lung), Seb Ross (hamstring), Dan McKenzie (calf) and Max King (shoulder) ahead of Sunday's match with Hawthorn.

However, Zaine Cordy will return from the AFL's 12-day concussion protocols and should replace Howard in the Saints' side. Jack Hayes could also return, having dealt with a hamstring injury.

The Saints also expect Tim Membrey to recover from a long-term knee injury through the VFL this weekend, while King remains an outside chance to make a speedy return ahead of next week's fixture with Carlton.

Howard has played in all 18 of St Kilda's games so far this season, forming a nice defensive partnership with important vice-captain Cal Wilkie and the club's chief interceptor Josh Battle.

The Saints are sixth on the ladder, two points inside the AFL's finals positions with five games to play, but have struggled recently and have won only two of their last six matches.