Cox, who tore his hamstring in Fremantle's round-one win over the Brisbane Lions, is pushing hard for an AFL recall after making it through two WAFL hit-outs unscathed.
The 25-year-old made it through training on Wednesday, and coach Justin Longmuir gave a strong indication that Cox would face the Tigers.
"If you see him come off training at the end of the session and he's got through, there's a fair chance he'll play," Longmuir said before the session.
Cox is set to replace two-game defender Hugh Davies.
Walters is also technically available after recovering from the hamstring strain he suffered against the Western Bulldogs on June 15.
The 33-year-old was set to miss three to four weeks with that injury, and a return against Richmond would put it at three.
Longmuir hinted that Walters may need another week before being unleashed again.
"It's a bit different with Sonny (Walters) and Coxy. Coxy's had a two-week build and hasn't missed a beat with his build, and Sonny's still in his injury rehab," Longmuir said.
"We'll see where he's at after (training), both physically and where his mind is at, and we'll make a call from there."
Michael Walters hobbles off during Freo's big loss in round 14 to the Western Bulldogs. (James Ross/AAP PHOTOS)
Fremantle have covered the loss of Walters by playing an extra midfielder, allowing the likes of Hayden Young, Caleb Serong, Andrew Brayshaw and Nat Fyfe to spend longer stints up forward.
The tactic has worked well, with the Dockers defeating Gold Coast by 20 points before scoring a thrilling one-point win over the ladder-leading Swans at the SCG.
That win over Sydney rocketed Fremantle (9-5-1) into third spot, and thrust their name into the premiership conversation.
Despite the success of the midfielders in attack, Longmuir said there's still room for Walters when he's ready to return from injury.
"Sonny's played a lot of footy and kicked a lot of goals and is one of our more dangerous forwards," Longmuir said.
"He hasn't been out of the team for that long, and he was part of a really dangerous forward line against Melbourne (when we won by 92 points)."
Skipper Alex Pearce will miss at least two more games with a fractured forearm.
Moose on track 🫎— Fremantle Dockers (@freodockers) #foreverfreo pic.twitter.com/xwqv4zfngDJuly 3, 2024
Longmuir will notch his 100-game milestone as Fremantle coach in Saturday's match, following on from his 139 games for the Dockers as a player.
"I always wanted to be a senior coach, but I always wanted to coach here as well deep down," Longmuir said.
"It's a club I'm really grateful for the opportunities that I've been presented and what they've given to me in my journey.
"I'll be forever indebted to repay that."
