The news of his passing was shared on social media by Jon's bandmates -- from his other rock group Lydia's Castle -- who confirmed the drummer died Saturday evening while surrounded by his family and friends.

Though the members of Lydia's Castle did not share Jon's cause of death, the musician was reportedly having issues with his liver -- requiring medical care.

Jon's former bandmates from his time in SOIL also issued a statement about his death, remembering him as "one of the greats."

They continued ... "Jon Wysocki was not only a great friend, a great drummer, but a great human being. It was an honor to have him in SOIL for the time we did. We had so many laughs, so many good times. You will be missed dearly. Until we meet again dear friend…."

Jon rose to prominence by forming Staind with singer Aaron Lewis, guitarist Mike Mushok and bassist Johnny April in 1995. He notably stayed with the group for almost 2 decades ... exiting in 2011, with Sal Giancarelli eventually replacing him.

Despite going their separate ways years ago, Aaron remember Jon fondly while paying tribute to him on Sunday.

He wrote on X ... "I’m so sad. I lost my friend. A friend I loved like a brother… fought with like a brother… cared for like a brother… worried about like a brother… cried over like a brother… because he was my brother in arms. My journey would’ve been different without him."

Jon was 53.