A tragic report comes from the camp of UFC welterweight Jake Shields. His father and longtime fight manager, Jack Shields, passed away yesterday.

Jake's mother posted the unfortunate news on her Facebook page earlier this morning.

Billie Shields Jack passed away unexpectedly, yet gently yesterday..hes been a light in my life...truely part of me

Jack first assumed the role of coach and mentor when Jake was just nine years old and competing in amateur wrestling. His tutelage continued for ten years until Jake crossed over to mixed martial arts. After nine fights in their home state of California and one in Hawaii, Jake got the opportunity that would end up launching his career.

The offer was to face Japanese legend Hayato Sakurai overseas in the Shooto organization. "Mach" was a former Shooto Middleweight Champion who had recently lost the belt to Anderson Silva and was fresh off an unsuccessful shot at Matt Hughes' title at UFC 36. Shields pulled off a shocking upset and defeated the crafty veteran by decision in 2002, putting the young submission grappler's name on the map.

Despite the surge in recognition, appealing offers were not pouring in, so Jake decided to once again seek guidance from his father to help find opponents and review incoming fight contracts. Jack Shields reminisced about reconnecting with his son in an interview with Ben Fowlkes of MMAFighting in April of 2011.

"Jake asked me to manage him after that and I said, 'I'm sure there's someone down there who knows the business a lot better than I do. I'm all the way up here in the mountains. There's got to be someone closer to you who knows this business.' Six to eight months later he sent me a contract that somebody wanted him to sign and then I took over. It was terrible. I had to [delete] the whole thing and write a new one."

Their partnership proved to be extremely beneficial. More details in the full entry.

Jake went on to become the Shooto Middleweight Champion, the 2006 Rumble on the Rock Welterweight Champion, the EliteXC Welterweight Champion and the Strikeforce Middleweight Champion while holding a top-ten ranking for many years at 170- and 185-pounds.

The journey led to Jake finally achieving his life-long dream of fighting on MMA's biggest stage against alpha welterweight and top pound-for-pound candidate Georges St. Pierre. Even though the unstoppable Canadian snapped his fifteen-fight win streak that spanned five years, there's no question that Jake Shields has accomplished more in MMA than most ever will and his father was a crucial component to his success.

Graciefighter.com posted the following note today:

The father of Jake Shields has passed away. It was learned that he died peacefully as he slept. Jack Shields was instrumental in his son’s MMA career. He taught Jake the values of hard work and perseverance. He was always there and was a fervent supporter through Jake’s early years in wrestling and when Jake transcended to MMA. Jack would often make the long drive from his home to watch Jake practice and was always at Jake’s fights. He was part of our team and we will miss him. “lost my father manager and one of my best friends today!! R.I.P jack you will be greatly missed and loved by many” – Jake Shields

Jack Shields was 67-years old. Jake is tabbed to meet Jake Ellenberger at "UFC Fight Night: Shields vs. Ellenberger" on September 17.