Young Fremantle midfielder Neil Erasmus made a statement on the opening day of pre-season training, blitzing Fremantle's first two time trials after building his tank during the off-season.

Erasmus, who played five games in his debut season in 2022, set the standard early to win two of the club's four 1km time trials, with midfielder Caleb Serong and defender Heath Chapman winning the third and fourth respectively.

The final time trial saw Chapman win from Serong and Michael Frederick, with second-year midfielder Matthew Johnson and defender Hayden Young rounding out the top five.

Over the four runs, it was Serong who placed first overall for aggregate time, ahead of Chapman in second, Michael Frederick in third, Erasmus in fourth and Matthew Johnson in fifth.

Serong said the return to training on Monday, which included skills and ball movement work following the running trials, had highlighted the hard work put in by players like Erasmus during the off-season. 

"He's in incredible nick … he made some great strides last year and his fitness is definitely one of his strengths," Serong said of the 18-year-old. 

"I think he really wanted to hone that this off-season and he's been working incredibly hard.

"To come out in those first two and really put himself in a hole and work really hard and try to hold on, it's a credit to him and his mental toughness."

As well as Erasmus, Serong said he had been impressed by Chapman and Matthew Johnson on their returns.

Premiership ruckman Luke Jackson also completed his first official session as a Fremantle player, moving well in drills and running competitively through the time trials.

"He's a great runner for a man of his size and you saw that today," Serong said. 

"He's been buzzing around in the gym and running sessions, so he's fitting in really well."

Key forward Matt Taberner and tall defender Joel Hamling were among the senior players to hit the track early, with Sam Switkowski, Michael Walters and James Aish also involved at the Dockers' Cockburn base.

Serong said the Dockers players had been holding skills sessions with a group of more than 20 players through the off-season, with defenders Jordan Clark, Young and Chapman driving the extra sessions.   

"The pleasing thing about our group at the moment is we can trust everyone's done the work," Serong said. 

"It's really pleasing to see guys coming back in great nick and I've got no doubt the guys coming back next week will be in the exact same boat."

Entering his fourth season, Serong said he was focused on building his strengths this pre-season and turning them into "weapons" in 2023.

"For me that's contest, that's always a big focus for me, and then the running and getting out of stoppage. That's where my game is centred," he said. 

"I understand there's weaknesses and areas of improvement for me and they're going to keep ticking along.

"But really trying to make my strengths weapons and trying to hone that. That's a big focus for us over this pre-season, to make our strengths weapons and really make them stand out."