#4 Kurt Angle (Left WWE in 2006)
The Olympic Gold Medalist will go down in WWE history as one of the most gifted, charismatic, and consistent performers of all time. In his first stint with the sports entertainment giant, Kurt Angle put on stellar matches with the stars of both the Attitude Era as well as the Ruthless Aggression era.
In 2006, WWE launched ECW under its umbrella and made it a weekly episodic show. Kurt Angle was one of the Superstars who made the jump to boost the credibility of the extreme brand.
However, early on in his ECW run, the six-time World Champion suffered a groin strain as well as tore his hamstring and abdominal muscle. While he proceeded to wrestle Sabu after sustaining the aforementioned injuries, it was clear in Angle's mind that he had to leave WWE.
On August 25, 2006, Angle was granted an early release from his contract so he could work on his mental and physical health. While this decision shocked the WWE Universe, it was the only logical step the company could take at that time.
But barely two months later, Kurt Angle made his TNA debut and wrestled there for nearly a decade.