St Kilda will look to stretch Sydney's defence when the clubs clash in Docklands on Saturday afternoon.

The Saints have made three changes for the Round 9 encounter, one of which is the inlcusion of young forward Paddy McCartin.

The number one draft pick from 2014 hasn't featured at AFL level since Round 3 but returns following strong form for St Kilda's VFL affiliate Sandringham.

The 21-year-old tallied four goals, 18 disposals and 14 marks for the Zebras in last Sunday's fixture.

He replaced fellow foward Josh Bruce in the Saints' selected 22, announced on Thursday night.

Meanwhile, Koby Stevens and Daniel McKenzie also make their returns for the Saints in place of Jimmy Webster (hand) and Darren Minchington (omitted).

Stevens and McKenzie add further run to an already energetic outfit coming off three consecutive wins.

One of the form sides of the competition, St Kilda will look to use their midfield strength and tall timber to their advantage in what is Sydney's second game at Docklands in as many weeks.

Jack Billings will be a player to watch after the speedy midfielder collected 30 disposals and kicked five goals in last weekend's win against Carlton.

He's just a number of players in their midfield group who are in strong form.

It's their quick ball movement from these types which make their forward line, featuring former Swan Tim Membrey, one of the most dangerous in the competition.

They rank second in the league for marks inside 50 which means they create opportunities but inaccuracy in front of goal (ranked 15th for goal accuracy) has hurt them.

The Saints play pretty well at Docklands, having won four of six matches at their home ground, including an emphatic 23-point win against GWS in Round 7.

Recent history against Sydney however isn't in their favour having lost eight of the past nine games overall, and three of the last four under the Docklands roof.