SYDNEY defender Heath Grundy will miss the Swans' crunch clash with Collingwood on Saturday night because of his mental health.

It is unclear whether Grundy's absence is related to his delayed start to the second half against Essendon last week, when he eventually returned to the field as a forward.

In other selection news, Jimmy Webster is back for St Kilda, North Melbourne regains Jarrad Waite, Brodie Smith and Tom Doedee are in for Adelaide, and Liam Ryan is in the mix to return for West Coast.

Greater Western Sydney will also be without Tim Taranto (knee) and Dylan Shiel (ankle) for Sunday's match against Carlton.

FULL TEAMS Check 'em out here

Connor Menadue and Sam Lloyd are Richmond's replacements for premiership players Dion Prestia (ribs) and Nathan Broad (calf) on Friday night.

The Tigers face Geelong, which promoted debutant ruckman Ryan Abbott and Jamaine Jones to cover for in-form defender Tom Stewart (ankle) and Quinton Narkle (funeral).

Hawthorn young gun Harry Morrison's return at Jono O'Rourke's expense in the only change for either side in the Hawks' must-win meeting with Essendon at the MCG on Saturday afternoon.

Brandon Starcevich will make his AFL debut for Brisbane against North Melbourne at the Gabba on the same day.

The Lions also included Ryan Bastinac and dumped Jake Barrett and Ryan Lester, while Waite's inclusion for the Roos comes as Brownlow Medal fancy Shaun Higgins (knee) goes out.

Port Adelaide looks set to enter Showdown 45 with an unchanged line-up, but it's a different story at Adelaide.

Brodie Smith will make his AFL return for the Crows after recovering from a knee reconstruction and playing a pair of SANFL matches.

Cam Ellis-Yolmen, David Mackay and Tom Doedee are also back, while Jake Kelly is a surprise omission along with Mitch McGovern (shoulder), Kyle Cheney (suspension) and Paul Seedsman (hamstring).

Webster's return from a fortnight out with a groin injury headlines St Kilda's inclusions, on top of Nathan Freeman's long-awaited debut after repeated hamstring setbacks.

Joining them in the Saints' side to take on the Western Bulldogs are top-10 draft pick Hunter Clark and veteran David Armitage.

Omitted pair Sam Gilbert and Rowan Marshall, as well as Mav Weller (general soreness) and Shane Savage (hamstring) make way.

Roarke Smith, Tory Dickson – for his first match since round 11 – and Lin Jong come in for the Dogs, who lost Marcus Adams (shoulder) and dropped fellow defender Fletcher Roberts and Mitch Honeychurch.

Grundy's shock unavailability comes as the Swans select Alex Johnson for his first game since the 2012 Grand Final and regain Kieren Jack, Jarrad McVeigh and Dan Robinson.

They dropped Robbie Fox, but lost Irishman Colin O'Riordan (hip) and Zak Jones (suspension), on top of Grundy.

Basketball convert Jack Madgen will play his first match for the Magpies against Sydney, with Brayden Sier back from his leg injury.

Defenders Jeremy Howe (concussion) and Matt Scharenberg (knee) are Collingwood's significant outs.

Carlton is yet to drop anyone as it tries to back up last week's defeat of Gold Coast against the Giants on Sunday.

Cam O'Shea and Sam Kerridge are two of the four possible additions.

Along with Shiel and Taranto, GWS also lost Sam Reid to injury, but is set to bring back star forward Jeremy Cameron (suspension) and Matt de Boer, and could hand No.11 draft pick Aiden Bonar his AFL debut.

Aaron vandenBerg will play his first game in almost two years for Melbourne, which loses Jake Melksham (hamstring) for its Sunday clash with Gold Coast.

Pearce Hanley and Michael Barlow are among the possible Suns inclusions to replace injured duo Rory Thompson and David Swallow and suspended captain Steven May.

Lewis Jetta and Luke Shuey are in line to return for West Coast against Fremantle at Optus Stadium in the round's final match.

The Dockers could benefit from the return of Matt Taberner and Hayden Ballantyne, with Cam Sutcliffe (hamstring) the sole confirmed out.

Friday, August 3

Richmond v Geelong at the MCG, 7.50pm AEST

RICHMOND

In: S.Lloyd, C.Menadue

Out: D.Prestia (ribs), N.Broad (calf)

GEELONG

In: R.Abbott, J.Jones

Out: Q.Narkle (funeral), T.Stewart (foot)

New: Ryan Abbott (Geelong VFL)

Saturday, August 4

Hawthorn v Essendon at the MCG, 1.10pm AEST

HAWTHORN

In: H.Morrison

Out: J.O'Rourke

ESSENDON

No changes

Brisbane v North Melbourne at the Gabba, 2.10pm AEST

BRISBANE

In: B.Starcevich, R.Bastinac

Out: Ryan Lester, J.Barrett

New: Brandon Starcevich (East Perth)

NORTH MELBOURNE

In: J.Waite

Out: S.Higgins (knee)

Adelaide v Port Adelaide at the Adelaide Oval, 4.05pm ACST

ADELAIDE

In: D.Mackay, C.Ellis-Yolmen, B.Smith, T.Doedee

Out: J.Kelly, P.Seedsman (hamstring), K.Cheney (suspension), M.McGovern (shoulder)

PORT ADELAIDE

No changes

St Kilda v Western Bulldogs at Etihad Stadium, 7.25pm AEST

ST KILDA

In: N.Freeman, H.Clark, D.Armitage, J.Webster

Out: S.Savage (hamstring), M.Weller (soreness), S.Gilbert, R.Marshall

WESTERN BULLDOGS

In: T.Dickson, R.Smith, L.Jong

Out: F.Roberts, M.Honeychurch, M.Adams (shoulder)

Sydney v Collingwood at the SCG, 7.25pm AEST

SYDNEY

In: A.Johnson, K.Jack, J.McVeigh, D.Robinson

Out: R.Fox, C.O'Riordan (hip), Z.Jones (suspension), H.Grundy (mental health)

COLLINGWOOD

In: B.Sier, J.Madgen

Out: J.Howe (concussion), M.Scharenberg (knee)

New: Jack Madgen (Delta State University)

Sunday, August 5

Carlton v Greater Western Sydney at Etihad Stadium, 1.10pm AEST

CARLTON

In: C.O'Shea, P.Kerr, N.Graham, S.Kerridge

Out: Nil

GREATER WESTERN SYDNEY

In: M.de Boer, J.Cameron, D.Lloyd, A.Bonar, H.Perryman, I.Cumming, L.Keeffe

Out: T.Taranto (knee), D.Shiel (ankle), S.Reid (knee)

New: Aiden Bonar (Dandenong U18)

Melbourne v Gold Coast at the MCG, 3.20pm AEST

MELBOURNE

In: A.vandenBerg, D.Kent, C.Pedersen, J.Hunt, T.Smith

Out: J.Melksham (hamstring)

GOLD COAST

In: C.Ah Chee, M.Spencer, P.Hanley, J.Leslie, M.Barlow, J.Dawson, B.Ainsworth

Out: R.Thompson (injured), S.May (suspension), D.Swallow (injured)

West Coast v Fremantle at Optus Stadium, 2.40pm AWST

WEST COAST

In: L.Jetta, L.Shuey, L.Ryan, B.Ah Chee

Out: None

FREMANTLE

In: M.Taberner, H.Ballantyne, M.Crowden, B.Grey, C.McCarthy

Out: C.Sutcliffe (injured)