A FLIP of the coin, a roll of the dice or just a gut feel.

Whatever the method Fremantle uses, Richmond's midfielders will be hoping their number doesn't come up when Freo tagger Ryan Crowley is assigned an opponent for Saturday's AFL clash at Patersons Stadium.

Crowley has re-established himself as one of the best shutdown players this year, with the 28-year-old snaring the key scalps of Chris Judd, Scott Thompson and Luke Shuey among many others in 2012.

Another big job looms for the 134-game veteran against the Tigers, with one of Dustin Martin, Brett Deledio or Trent Cotchin in his sights.

Fremantle coach Ross Lyon is yet to decide on which star Tiger to target, and says he probably won't let Crowley know until the last minute to keep the match-up top secret.

"Sometimes, they've got mates at Richmond so they text and twitter," Lyon said on Thursday.

"So I just tend to leave it to the last minute before Ryan knows who he's getting."

Lyon said Shaun Grigg and Shane Tuck would also come under consideration for Crowley to tag, but it's one of Martin, Deledio and Cotchin who are almost certain to feel the heat.

Two weeks ago, Lyon said it was a flip of the coin as to whether Crowley would tag West Coast's Daniel Kerr or Shuey.

Unfortunately for Shuey, it ended up being him, with the emerging star restricted to just 11 disposals in his lowest AFL possession haul.

Last week, Crowley was assigned to Thompson, with the prolific Crow managing just 16 touches in his quietest game since round seven last year.

"I think Ross probably does flip a coin," Fremantle midfielder Nat Fyfe says of Lyon's method of choosing an opponent for Crowley.

"Last week was the (Patrick) Dangerfield or Thompson one.

"Crowley's a really selfless player and has had a big year for us."

Fyfe will return after missing last week when he tripped on his suitcase in his hotel room before the game.

Lyon said Chris Mayne was also available after being cleared of concussion and key defender Luke McPharlin set to return from suspension.

He said Fremantle had some important decisions to make around team balance if Aaron Sandilands played alongside ruckman Jon Griffin, who has been in strong form.

"We're going to train him forward today," Lyon said of Sandilands, who hasn't played since suffering a toe injury against Richmond in round 11.

"He's something unique and pretty hard to deal with, particularly with the rules with defenders taking arms and holding. That's a potential opportunity for us.

"Jon Griffin has been fantastic in the ruck with help from Kepler Bradley and Zac Clarke when he's played.

"It's been a pretty good model for us and we're trying to get our head around what are the opportunities if [Sandilands] plays. It's maybe another dimension up forward."

Nathan Schmook covers Fremantle news for AFL.com.au. Follow him on Twitter: @AFL_Nathan