"I'm not going to answer any more health questions on Hurst," Gruden said. "I realize there's a lot of ghost stories out there about unnamed sources. ... I hope you just judge him on the field. He's been cleared medically, and I'll just leave it at that."
On Thursday, Bleacher Report's Matt Miller reported strong comments from NFL sources about the Raiders' decision to pick Hurst in the fifth round of last month's draft.
One called the selection "irresponsible," adding they hoped the University of Michigan product would "never put a f--king helmet on again in his life."
"Only the Raiders would draft a guy who could literally die on the field from a known condition," an NFL head coach told Miller.
For his part, Hurst said Friday he wants to move past the health questions and start preparing for his rookie campaign.
"Just trying to get all that stuff behind me, try to get people to stop talking about it as some sort of issue or all those kinds of things," he told reporters. "Just try to move past that and focus on playing football and just having fun out there."
Hurst, who was viewed as a potential first-round choice before the health issue was reported, was a consensus All-American and a First Team All-Big Ten selection in 2017. He racked up 59 total tackles, 5.5 sacks and a forced fumble across 13 games for the Wolverines.
In Oakland, the defensive tackle is likely to compete with Eddie Vanderdoes and P. J. Hall for playing time alongside Justin Ellis in the middle of the line.