Fremantle defender Heath Chapman has agreed to a three-year contract extension with the Dockers, tying his future at the club to the end of the 2027 season.

The extension is an addition to the 20-year-old's current contract, which runs until the conclusion of the 2024 season.

After being selected by the Dockers with Pick 14 at the 2020 National Draft, Chapman made his debut in purple colours in Round 2 of the 2021 season.

However, Chapman truly made a name for himself in Round 1 of this season when he 'single-handedly' sealed victory for Fremantle against the Adelaide Crows.

Chapman cited the desire for long-term security as a key part of his thought process as he expressed his pleasure at being able to cement his future for years to come, while also praising the position the Dockers are currently in as a football club.

"I'm stoked to sign on for an extra three years until the end of 2027", Chapman told fremantlefc.com.au.

"It's good mentally for a bit of security and frees me up to put my best foot forward and not worry about anything else.

"Fremantle are in a really good spot. There's some very exciting times to look forward to but we're focused on the now and will finish off the rest of the season strong."

Fremantle player personnel boss David Walls acknowledged Chapman's increasing importance to the Dockers side and was pleased to be able to lock down the young backman for seasons to come.

"Heath has very quickly become super important to us. He's been really key down back with his ability to play tall and small and he's had a whole range of opponents," Walls said.

"We have a young backline that we think is going to be together for a long time so we're rapt to have him signed, extended out and committed to the Club.

"Heath is very aligned and committed with what we're trying to do, so it was great working with him and Andrew McDougall at Corporate Sports Australia to work through what is a significant deal in a really good fashion."

Walls also praised Chapman's ability to persevere through injury these first couple of years in the league.

"He hasn't played a huge amount of footy [due to injury] but the professionalism he's showed getting his shoulder right, he's been able to have an impact as soon as he returns," Walls said.

"That attitude and dedication shows he belongs at AFL level and we know he's going to get better and better each year."

Chapman joins rising half-back flanker Hayden Young in signing long-term agreements at Cockburn this season.