That's about to change.
Bush, a 6-3, 245-pound junior that looks more like a defensive end than running back, appears ready to assume the role as the Cardinals primary ball-carrier, and build on his 753 yard, seven touchdown sophomore campaign. And though he's no stranger to the field during game action, Bush will likely assume a new role next fall as U of L's short yardage back.
"Michael's doing great," Petrino said Wednesday. "He's really taken the bull by the horns as far as learning the running back position. He's really concentrating on his protections, and he can still make all of those open-field moves. I think what we've concentrated on him a lot (this spring) is the short-yardage and the goal line (situations) where we used to rely on Eric (Shelton). He's done a nice job. He gets his pads down low and pumps his legs."
Bush says he's trying to develop a more aggressive style to grind out the tough yards next season that almost became routine with Shelton last season.
"I've just got to be more aggressive and determined," Bush said. "Last year, I wasn't in very much in short yardage. I just came out (this spring) trying to learn the offense like the back of my hand. And right now I'm doing a good job. So it's a major step (forward) from last year."
Smith forms a potent duo with
Michael Bush in the Cardinals
"Playing fullback has made me a much better runner because I can anticipate what is going to happen," said Smith.
Smith enjoyed an outstanding scrimmage last weekend, carrying the ball 12 times for 70 yards and a game-high three touchdowns, scoring on runs of 4, 39 and 1.
"I think the experience Michael and Kolby gained their first two years has certainly shown up this spring," Nord said. "They've got to continue learning how to do everything in the offense, and be ready to play more downs in a row than they have. But I've pleased with the way they've looked."
While the duo will likely split time – and carries – in the backfield, it seems nearly certain they'll see time on the field together in certain situations.
"If playing them both at the same time is best (for the offense) that's what we'll do," Nord said. "They both have some obvious strengths and do certain things really well. They're both good players and I'd be happy with either one of them in the game."
"It'll be me, Kolby (Smith), and maybe (George) Stripling back there," Bush said. "We're just trying to provide us a one-two punch like Auburn had last year with (Ronnie) Brown and (Cadillac Williams). We're just trying to have fun, and work hard."
So who'll be the Cadillac for the Cardinals offense next season, Bush or Smith?
"Kolby's the Cadillac," Bush said. "They call me the Navigator because I'm so big."
And speaking of Stripling, a 6-0, 190-pound redshirt freshman from Jacksonville, Florida who has impressed with his speed, and ability to cut on a dime, it appears Petrino's backfield is well stocked for the future. And while he's currently behind both Bush and Smith on the depth chart at running back, he'll almost certainly see some quality action in '05. And if his game-high 21 carries for 87 yards during Saturday's scrimmage is any indication, they'll be no drop in talent from the junior duo to the talented rookie.
"George came here to play," Nord said. "He's a very talented player that we're going to have to get him to where he knows the offense so we can utilize his skills and work him into the offense."
Stripling has shown great speed
"It's not going to change," Smith said of the Cardinals productivity on the ground. "We can still pound the ball or get outside if we want to."
And while some things won't change, like Petrino's ability to establish a potent rushing attack, expect U of L quarterback Brian Brohm to throw more to the backs out of the backfield than Stefan LeFors did last season.
"Yes, I believe (we'll throw more to the backs)," said Smith. "And it'll provide more of a challenge for the opposing team's defense because we've got so many weapons on the field, especially when me and Michael are both on the field, and can catch the ball."
For the Smith, the goal this spring was clear.
"I just want to show the coaches that I'm a tough enough back to carry the work load," he said.
And if the first two weeks of spring drills are any indication, he'll be more than ready to carry his share of the load next season.