RICHMOND has officially added exciting West Australian prospect Sydney Stack to its list after an impressive two-month trial at Punt Road.

The 18-year-old was informed on Monday morning, taking the club's final available rookie position through the pre-season supplemental selection period (SSP).

As flagged by AFL.com.au last week, Stack had performed strongly over summer and joined the club's pre-season training camp to Queensland last month.

Living with coach Damien Hardwick since his arrival in Melbourne in December, Stack has put to bed any question marks over his professionalism that saw him overlooked in the NAB AFL Draft.

When addressing the playing group to chants of "Sydney, Sydney, Sydney," Stack thanked his new teammates for their support.

"I'd like to thank the club for giving me the opportunity to come and train, (a) great bunch of blokes and I couldn't picture myself at any other club," Stack said. 

"Thanks for making me feel comfortable over the last couple of months and can't wait to play alongside you and have a good time this year."

"We're delighted to welcome Sydney to the club, he's worked really hard to secure a spot on the list, and we know he'll continue to work hard to develop his football,” head of football Neil Balme said.

"Sydney's got great speed, skill, and competes really hard, so we're excited by what he'll bring to the team.

"We think that Richmond is a positive environment for him, and we're pleased with how he's settling into the Club and our football program."

Stack follows former St Kilda and Gold Coast forward Mav Weller to join the Tigers this off-season through the SSP.

After Carlton added Michael Gibbons and Matthew Cottrell to its list last week, it leaves six available list spots through the new rules introduced ahead of 2019.

The Blues have one berth remaining, while Melbourne, Gold Coast and Greater Western Sydney are expected to wait to decide until the mid-season draft.

HOW IT WORKS The latest on the mid-season draft

Stack joined superstar Dustin Martin in clocking laps at training in Monday morning's 90-minute hitout at Punt Road. 

Spearhead Tom Lynch continued to ramp up his fitness, joining in full ground drills before completing running under the watchful eye of fitness staff after his teammates left the track.

Oleg Markov trained away from the main group with his right knee strapped, alongside Shaun Grigg and Ryan Garthwaite (Achilles). 
Small forward Jason Castagna, who has been taken out of a moon boot after an ankle setback, ran strongly in an individual session.