WEST Coast has turned to speedster Jack Petruccelle as cover for provisionally suspended teammate Willie Rioli in Friday night's must-win semi-final against Geelong. 

The reigning premier's title defence was rocked this week, with the AFL announcing on Thursday that Rioli returned an "adverse analytical finding" two days after the Eagles' round 22 game.

Rioli is now unable to play while he is provisionally suspended, putting his season in serious jeopardy. 

Petruccelle played 19 games this season before being dropped before last week's finals victory over Essendon. 

The Cats have made two forced changes as they try to avoid a straight-sets exit after being the minor premiers. 

They've selected ruckman Rhys Stanley – a controversial late withdrawal for structural reasons last week – to take on West Coast pair Nic Naitanui and Tom Hickey. 

Joining Stanley as an inclusion is Cam Guthrie, who returns from a calf complaint, while injured pair Gary Rohan and Mitch Duncan are out. 

FULL TEAMS Check 'em out now

Greater Western Sydney and Brisbane have each made one forced change ahead of Saturday night's do-or-die semi-final at the Gabba.

In-demand Giants free agent Adam Tomlinson is back to replace retirement-bound Brett Deledio (calf), after surprisingly being dropped for last week's final against the Western Bulldogs.

Tomlinson is being strongly linked to Melbourne but could yet play a role in GWS's bid to win a maiden AFL premiership.

Lions coach Chris Fagan told reporters mid-week that no team could replace hamstrung winger Mitch Robinson's physicality, but hard-at-it tagger Nick Robertson is the man they will try.

Friday, September 13

Geelong v West Coast at the MCG, 7.50pm AEST

GEELONG

In: C.Guthrie, R.Stanley
Out: G.Rohan (injured), M.Duncan (knee)

WEST COAST

In: J.Petruccelle
Out: W.Rioli (suspended)

Saturday, September 14

Brisbane v Greater Western Sydney at the Gabba, 7.25pm AEST

BRISBANE

In: N.Robertson
Out: M.Robinson (hamstring)

GREATER WESTERN SYDNEY

In: A.Tomlinson
Out: B.Deledio (calf)