"I don't know what you do with Dez Bryant because when Deion Sanders gives up on you, that speaks volumes to me," Johnston told The Dallas Morning News at the Emmitt Smith Celebrity Invitational on Friday. "Deion goes out of his way to help young guys and try to help them reach their potential in the NFL. And when Deion says, 'I can't work with you anymore,' that's the first time he has ever done that.
"This is a person with unique talent but with unique issues. And it would be a disappointment for Dez, number one, his family, the Cowboys, and their fans, if he doesn't live up to the potential he flashed as a rookie. He was by far the most talented guy on that field many times during last fall. And the sky's the limit for that kid. And I just hope that at some point he understands and realizes that he shouldn't waste two or three years because his head is not in the game."
It has been an eventful offseason for Bryant, who has been sued by two jewelers and also had a run-in with security at a Dallas-area mall. He recently reached a settlement with a business owner over a $267,000 jewelry tab.
"Don't ever compare him to Michael Irvin because they are polar opposites," Johnston said. "Michael was high-profile and he had the 'playmaker' nickname, but Michael was the hardest worker on that team. So, one of things you have to be careful with is that all of a sudden (because) he's high-profile and he's dynamic as a player, you reach back and compare him to Michael. It couldn't be further from reality.
"We had big personalities but we had guys who came to work and all they wanted to do was win football games. And hopefully that's what Dez realizes -- that this is not about finishing your rookie contract."
Bryant, 22, had explosive moments as a rookie in Dallas before an ankle injury cut short his season. He finished with 45 catches for 561 yards and six touchdowns. He also was a dangerous special-teams threat, returning two punts for scores.