On the latest episode of Grilling JR, Jim Ross discussed Brock Lesnar leaving the WWE in 2004. 

"He burned out. He was burned out and getting bad advice from some of his peers I believe. He had this dream of playing in the NFL, and apparently had that dream for many, many years. He had been so focused and grounded in the amateur wrestling world that he never got to really do that. I just think he didn’t travel well at that time. He went from a dairy farm in South Dakota, and now he’s traveling the world regularly. I think it wore on him, and that could’ve been something we probably could’ve made better for him. I look at myself in the mirror on that deal. For him, he did really well in that camp. I think he was the last guy cut before the 53-man roster without playing college football at all.

I just think he didn’t fully understand the travel. We had him in OVW, and he didn’t travel. That was all local stuff. That was not the case here, and knowing the trajectory of where he was headed, it wasn’t gonna lessen. Any international tour was gonna include Brock Lesnar. Any major events were gonna include Brock Lesnar. I think he forecasted that a little bit. But it was very abrupt. We were not ready for that announcement that ‘I’m leaving.’ It was a little bit of a shocker and hard to process because Vince felt like we were treating Brock well and he was making a lot of money"