Bradtke, who has been training with the Tigers since December, becomes the latest SSP signing just one day before Wednesday's deadline.
The 21-year-old impressed at local level in 2022, kicking 39 goals from 17 outings for the Corowa-Rutherglen Kangaroos in the Ovens and Murray League.
Additionally, Bradtke featured twice for Sydney's VFL side in 2022 playing against North Melbourne and Sandringham, averaging eight possessions.
Richmond National Recruiting Manager Matt Clarke said the 21-year-old has shown exciting potential, despite being overlooked at the AFL National and Rookie Drafts.
“He is pretty raw, which is exciting- but already he has shown a strong desire to learn and improve, which gives us confidence he can flourish within our program,” Clarke added.
“Kaelan has played well in senior football- kicking goals against men as a main forward target in the Ovens and Murray.
“We think he has the tools to develop into a player that will be hard to play on at the elite level, so we are delighted to be giving him this opportunity at Richmond.”
Possessing great speed and agility, Bradtke was held in high regard at Rooland under with former Roos’ coach and185-gamer with North Melbourne Peter German describing him, “in the top five athletes I’ve coached in 30 years. He’s a unique specimen of an athlete, a quality tall.”