FREMANTLE defender Brennan Cox says becoming a dad for the first time helped him through the "gloomy" rehab while he was nursing a serious hamstring injury.

Cox tore his right hamstring during the club's season-opening win over Brisbane, with the injury requiring surgery.

Two weeks after going under the knife, Cox welcomed the birth of his first child, Arlo.

The new arrival helped Cox during his three-month stint on the sidelines.

Cox returned via the WAFL last month, and he was back in the senior ranks on Saturday night, tallying 14 disposals as Fremantle beat Richmond by 51 points at Optus Stadium.

The return was just reward for Cox, who was also sidelined for a large chunk during the off-season after suffering a stress reaction in his fibula.

Cox's time in rehab was a bit more tolerable this time around. 

"Becoming a dad made it a fair bit easier. I was able to take my mind off things," Cox told reporters on Monday.

"It does get a bit gloomy in rehab. You try to stay pretty positive.

"And having Oscar McDonald (knee) and Josh Corbett (hip), who have done long stints in there, puts your hammies in perspective."

Cox is yet to regain full confidence in his surgically repaired hamstring.

That was clear when he didn't push himself to full pace when Richmond speedster Shai Bolton raced towards goal on Saturday night.

Cox pulled up well from the game, and knows his confidence will build bit by bit.

"I'm pretty confident in the whole body. It's more just the hamstring - as I continue to play I'll get more and more confident in it," he said.

Cox's return was all the more timely following the recent injury to skipper Alex Pearce (fractured arm).

Pearce has missed the past two games, and will also sit out Saturday's clash with Hawthorn in Launceston.

Fellow defender Josh Draper is also in doubt after suffering a corked leg against Richmond, but Brandon Walker (shoulder) could return.

Wins over Sydney and Richmond have thrust Fremantle (10-5-1) into third spot on the ladder, just half a win adrift of the second-placed Blues.

But the ladder is so tight that 10th-placed Melbourne (9-7) is only one and a half wins behind the Dockers.

"There is an excitement about how we're playing at the moment," Cox said.

"But the eight, it's really close. Two losses and you're pretty much back out the eight.

"Hopefully we can keep winning."