“I’ll help along the way with leadership but my priority is playing and I will let my actions do the talking,” Birchall told RSN on Wednesday.
“The past three years I have really struggled with injury and there have been challenges along the way.
“It has been a real grind being in rehab and I thought a fresh, new environment would do me the world of good.
“And Brisbane have a good track record of getting their players out on the park.”
Birchall played in the Hawks’ 2008 and 2013-15 premierships but has been ravaged by injuries, managing just eight games in the past three seasons.
The Lions have done well turning around the fortunes of recruits with previously chequered injury records.
Ex-Geelong small forward Lincoln McCarthy joined the Lions after playing 29 games in seven injury-plagued seasons at the Cats.
He went on to make 24 appearances for the Lions in 2019 including the club’s first finals matches in a decade.
“I feel that with a full pre-season with Brisbane I am confident that I will get my body right and be able to get out on the park and make a contribution,” Birchall said.