He turned down offers from several more established programs (including Ohio State) to stay at home and attend the University of Louisville, largely because head coach Bobby Petrino promised the opportunity to play quarterback, his preferred position.

Though he was not the starter, Bush was able to rush for 100 yards in back-to-back games as a running back toward the end of the year against Houston and Cincinnati.

[2][3] Meanwhile, Petrino had decided to recruit another star quarterback from the Louisville area: Brian Brohm of Trinity.

Though Bush had played various positions his freshman year, he believed this arrangement to be temporary and still expected to be a quarterback in the long-term.

[4] Bush's breakout season came as a junior in 2005, as he rushed for 1,143 yards on 205 carries, averaging 5.6 yards per carry, racked up a Big East-leading 23 rushing touchdowns, and was second in NCAA Division I-A in scoring to LenDale White.

He then scored two more touchdowns in the first half, and had carried for 128 yards when he was tackled by Kentucky linebacker Wesley Woodyard during a routine rushing play in the third quarter and suffered a broken right tibia.

The injury was so bad that ESPN announced before the end of the game that Bush would miss the remainder of the 2006 season.

[9] The injury required the insertion of a steel rod and a second operation to facilitate the healing process.

In the win, Bush rushed for 177 yards on 27 carries and two touchdowns to help Oakland deny Tampa Bay a spot in the playoffs.

[23] In Week 10, he started as running back against the San Diego Chargers in place of the injured McFadden.

[31] Bush was also unofficially considered the emergency quarterback of the Bears, something which is related to his experience from high school.

"[36][37][38] Bush's wife Emily, an Australian, is the half-sister of National Basketball Association player Ben Simmons.