The 23-year-old recently went in for scans which revealed the fracture, meaning he will miss at least the first round of home-and-away action.
Hawks physical performance manager Luke Boyd shed light on Bramble's ailment and what the plan is for him moving forward.
"Lachie developed some foot soreness towards the end of the game last Friday night, post-game [he] was quite sore", Boyd told the club's official website.
"We had a bit of a look at that and [upon] further investigation on Saturday, and unfortunately for Lachie, [it's] revealed that he has a stress fracture in his foot.
"So, what that means from here is we'll obviously immobilise him and keep him pretty low-key [and] that will mean he won't be available for Round 1.
"The next couple of weeks will give us a pretty good indication of how he settles [and] how long we expect Lachie will be out of footy for."
Bramble, a 2021 pre-season supplementary selection, debuted in Round 14 last year and played in all 10 of the Hawks' remaining games, showcasing his hardness at the contest and willingness to win the ball and distribute.
In just his fourth taste of AFL action, Bramble notched a career-best 27 disposals, six marks, two tackles and eight rebound-50s in a loss against the Dockers.
In other injury news for the Hawks, draftee Jai Serong and midfielder Daniel Howe will also be absent during Hawthorn's AAMI Community Series match-up against Richmond after both players suffered head knocks last week.