This spring, he'll get a chance to show new defensive coordinator Mike Cassity what he can do at safety, too.
"Michael Bush will work both offensively and defensively this spring," Petrino said. "So we're going to be able to get a look at him on both sides of the ball. And that's something that he's interested in doing. So it's really intriguing to him.
Bush, who rushed for over 400 yards and 6 touchdowns as a freshman, has been working hard in the weight room during the offseason.
"He's been working hard in the weight room," Petrino said. "He's shed weight and put on strength and he's continuing to do a great job for us."
So why move Bush to defense during the spring?
"When you see a guy that big that can move and do the things he can, he's an amazing athlete," Petrino said. "I'm just looking forward to seeing him on both sides of the ball to see how he does during the spring."
Bush, Kentucky's Mr. Football as a senior in high school, was also an All-State safety at Louisville Male High School.