WEST Coast has regained ruckman Nic Naitanui and forward Mark LeCras for Sunday's top-four clash with the Western Bulldogs at Domain Stadium.

And forgotten Geelong ruckman Nathan Vardy will make his long-awaited return to the AFL after being named to face St Kilda on Saturday night at Etihad Stadium. 

Naitanui returns to the Eagles' line up after missing two games following the death of his mother, while LeCras is back after a one-match suspension.

With Sam Butler (hamstring), Will Schofield (hamstring), Chris Masten (suspension) and Scott Lycett (knee) forced out, the second-placed Eagles have had to shuffle their side.

In their squad they have included defender Tom Barrass, midfielder Kane Lucas, who is in line for for his Eagles' debut, Murray Newman, who has not played since round 17, 2012, Jackson Nelson and first-year forward Tom Lamb.

The Bulldogs will travel without veterans Matthew Boyd (soreness) and Liam Picken (back), and have omitted Sam Darley after two senior games.

Promoted rookie and "free spirit" Roarke Smith will play his first AFL game after solid VFL form across half-back.

Defender Jason Johannisen is in the squad after a two-week hamstring, along with Tom Boyd following a month in the VFL and Brett Goodes for potentially his first game since round eight. Bailey Dale and Daniel Pearce are chances – Pearce for the first time this season.

Jason Holmes will become the first US-born and raised athlete to play an AFL game when he lines up for St Kilda on Saturday night against Geelong at Etihad Stadium.

Billy Longer has been sidelined by a shoulder, as a spate of injuries forced seven changes to the Saints' side, with David Armitage (shoulder) and Sean Dempster (nose) headlining the outs.

Dylan Roberton (ankle), Nathan Wright (finger), Blake Acres (quad) and Jack Sinclair (shoulder) are also out, with veteran Farren Ray and young midfielder Luke Dunstan among the inclusions with Tim Membrey, Cameron Shenton, Shane Savage and Brodie Murdoch, for his first AFL game for the season.

Vardy, who returns after a knee reconstruction, will line up for his first Geelong game since the 2013 preliminary final.

Defenders Tom Lonergan and Jed Bews are in, with Jared Rivers to miss with a knee injury.

Veteran James Kelly is out with an ankle  while Mathew Stokes has been omitted, with the Cats holding fire on the return of Daniel Menzel for at least another week.

Hawthorn has made one change for Friday night's clash with Port Adelaide at Etihad Stadium, with first-year utility Daniel Howe dropped for Ryan Schoenmakers.

The Power have resisted the temptation to recall ruckman Matthew Lobbe, despite his 62 hit-outs in the SANFL last week, and have made just one change for Friday night, with Jay Schulz in after missing one week with a sore back and Jackson Trengove headed for a season-ending shoulder reconstruction.

With Tyson Goldsack unavailable because of continuing issues with his knee tendinitis, Collingwood has called up half-back Brayden Maynard to face Richmond, with Nathan Brown suspended.

The Tigers have regained Shane Edwards from a fractured leg that cost him five games, with midfielder Matt Thomas making way.

Greater Western Sydney has lost co-captain Phil Davis for Saturday's clash with the Sydney Swans with a hamstring injury. Also out are Devon Smith with a knee issue and the rested Jack Steele, with Adam Treloar, Stephen Coniglio and Caleb Marchbank returning.

There's still no Lance Franklin for the Swans, who have lost Luke Parker to a nasty leg break. Gary Rohan is out with a knee issue and Tom Mitchell will miss with an injury to his eye.

Dean Towers and Zak Jones have been called up, while first-year forward James Rose has been picked for his debut.

Gold Coast forward Charlie Dixon has failed to come up from his recurrent ankle injury, aggravated last week against Richmond, and won't face Essendon at Metricon Stadium on Saturday. Jarrod Harbrow and Tom Nicholls are out with knee injuries while Clay Cameron and Andrew Boston have been omitted.

Zac Smith comes in for Nicholls and Rory Thompson returns from an ankle injury while Danny Stanley, Sean Lemmens and Henry Schade have been called up.

With caretaker Matthew Egan at the helm at Essendon for the first time, Michael Hurley is back to bolster their defence after missing three games with a knee injury, while Shaun McKernan replaces Jonathan Giles (knee). David Myers is out with a back complaint, while Tayte Pears, Ariel Steinberg and Kyle Langford have been omitted.

Nick O'Brien is back after 37 touches in the VFL while Patrick Ambrose and Orazio Fantasia have also been called up.

Adelaide midfielder Richard Douglas has been named for Saturday night's clash with the Brisbane Lions at Adelaide Oval, having missed the past two games after surgery to remove his appendix.

Sam Shaw has also been brought into the Crows' side with David Mackay omitted and first-year defender Jake Lever rested.

Meanwhile, the Lions have been forced to make one change despite their big win over Carlton last week, their first victory in three months.

Midfielder Daniel Rich is out with a glute injury and has been replaced by forward Josh Green, who comes straight into the senior side after a six-week foot stress fracture.

North Melbourne has named Ryan Bastinac and Trent Dumont as potential replacements for the suspended Jack Ziebell for Sunday's clash with Fremantle at Etihad Stadium.

Jamie Macmillan, Aaron Mullet and Brad McKenzie have also been picked in an expanded squad, with Taylor Garner the only other unforced omission at this stage.

An Achilles injury will see Matthew Pavlich miss the Dockers' second trip to Docklands in two weeks but the captain is expected to be sidelined for just one game.

Defender Alex Silvagni is suspended for the next four, but Luke McPharlin has been named to return from a calf injury along with Zac Dawson and Zac Clarke.

Connor Blakely was held over as the emergency last Sunday and has been picked again in the squad, along with another potential debutant in Ed Langdon.

Lachie Henderson has played his last game for Carlton after telling the club he wants to be traded and won't line up against Melbourne on Sunday at the MCG.

John Barker has named Levi Casboult after a week out with a knee and Matthew Watson following a lengthy VFL stint as his potential replacements, with Jason Tutt also in the squad.

Troy Menzel did enough at VFL level last week to be named as a potential inclusion but Chris Yarran remains on the outer.

Forgotten Demons' ruckman Mark Jamar has been named for what could be his first AFL game since round five while Christian Salem is in the squad after missing last week with illness.

Aidan Riley, Ben Newton and Billy Stretch have also been selected in the squad with Neville Jetta out with a neck injury and Matt Jones omitted.

All the ins and outs for round 21

Friday, August 21

Hawthorn v Port Adelaide at Etihad Stadium, 7.50pm AEST

Hawthorn
In: R.Schoenmakers
Out: D.Howe

Port Adelaide
In: J.Schulz
Out: J.Trengove (shoulder)

Saturday, August 22

Collingwood v Richmond at the MCG, 1.45pm AEST

Collingwood
In: B.Maynard
Out: N.Brown (suspension)

Richmond
In: S.Edwards
Out: M.Thomas

Greater Western Sydney v Sydney Swans at Spotless Stadium, 2.10pm AEST

GWS
In: A.Treloar, S.Coniglio, C.Marchbank
Out: P.Davis (hamstring), D.Smith (knee), J.Steele (rested)

Sydney Swans
In: D.Towers, J.Rose, Z.Jones
Out: L.Parker (leg), G.Rohan (knee), T.Mitchell (eye)
New: James Rose (Sturt)

Gold Coast v Essendon at Metricon Stadium, 4.35pm AEST

Gold Coast
In: D.Stanley, Z.Smith, R.Thompson, S.Lemmens, H.Schade
Out: J.Harbrow (knee), C.Dixon (ankle), T.Nicholls (knee), C.Cameron, A.Boston

Essendon
In: M.Hurley, S.McKernan, N.O'Brien, P.Ambrose, O.Fantasia
Out: D.Myers (back), J.Giles (knee), T.Pears, A.Steinberg, K.Langford

St Kilda v Geelong at Etihad Stadium, 7.20pm AEST

St Kilda
In: F.Ray, S.Savage, C.Shenton, L.Dunstan, T.Membrey, B.Murdoch, J.Holmes
Out: S.Dempster (nose), D.Armitage (shoulder), D.Roberton (ankle), B.Longer (shoulder), N.Wright (finger), B.Acres (quad), J.Sinclair (shoulder)
New: Jason Holmes (US)

Geelong
In: T.Lonergan, N.Vardy, J.Bews
Out: J.Kelly (ankle), M.Stokes, J.Rivers (knee)

Adelaide v Brisbane Lions at Adelaide Oval, 7.10pm ACST

Adelaide
In: R.Douglas, S.Shaw
Out: D.Mackay, J.Lever (rested)

Brisbane Lions
In: J.Green
Out: D.Rich (glute)

Sunday, August 23

North Melbourne v Fremantle at Etihad Stadium, 1.10pm AEST

North Melbourne
In: R.Bastinac, J.Macmillan, A.Mullett, B.McKenzie, T.Dumont
Out: J.Ziebell (suspension), T.Garner

Fremantle
In: L.McPharlin, Z.Dawson, Z.Clarke, E.Langdon, C.Blakely
Out: M.Pavlich (Achilles), A.Silvagni (suspension)
New: Ed Langdon (Sandringham U18), Connor Blakely (Swan Districts)

Carlton v Melbourne at the MCG, 3.20pm AEST

Carlton
In: J.Tutt, L.Casboult, M.Watson, T.Menzel
Out: L.Henderson

Melbourne
In: M.Jamar, A.Riley, B.Newton, C.Salem, B.Stretch
Out: N.Jetta (neck), M.Jones

West Coast v Western Bulldogs at Domain Stadium, 2.40pm AWST

West Coast
In: M.LeCras, N.Naitanui, K.Lucas, M.Newman, J.Nelson, T.Lamb, T.Barrass
Out: S.Butler (hamstring), W.Schofield (hamstring), C.Masten (suspension), S.Lycett (knee)

Western Bulldogs
In: J.Johannisen, R.Smith, D.Pearce, B.Goodes, T.Boyd, B.Dale
Out: M.Boyd (general soreness), L.Picken (back), S.Darley
New: Roarke Smith (Calder U18)