Michael Bush made the most of his first game of any kind in nearly two years.

Bush scored on a 5-yard touchdown run in his first game since breaking his leg in college more than 23 months ago, leading the Oakland Raiders to an 18-6 exhibition victory over the San Francisco 49ers on Friday night.

While Bush was the offensive star for the Raiders, the 49ers didn't get much from any of their three quarterbacks competing for the starting job in the exhibition opener.

J.T. O'Sullivan, who got the start, turned the ball over twice in four drives. Alex Smith, the No. 1 overall pick in the 2005 draft, led the Niners to a field goal late in then first half but was unable to generate a first down on his other two drives. Shaun Hill threw an interception on his first drive.

Oakland quarterback JaMarcus Russell also struggled in his first exhibition game after missing the entire preseason as a rookie in a contract dispute. Russell, who played in just four games as a rookie, was not sharp, finishing 2-for-5 for 15 yards in two drives.

The Raiders had much more success running the ball, gaining 248 yards on the ground. Rookie Darren McFadden, the fourth overall pick in the draft, ran for 48 yards on 12 attempts in his debut.

Bush ran for 27 yards and added 29 yards receiving in his first game since before breaking his leg on Sept. 3, 2006, while at Louisville. He missed the rest of that season and went from a possible first-round pick to a fourth-rounder. The rehabilitation then took longer than anticipated and Bush missed all of his rookie season as well.

With 1,000-yard rusher Justin Fargas and McFadden ahead of him on the depth chart, Bush needs to show off his skills in short yardage and receiving to find a role on the team. He did just that, converting four of his five short-yardage attempts for first downs and going 23 yards on a screen from Andrew Walter.

Bush's touchdown came when he bulled his way through the middle on a fourth-and-1 play midway through the third quarter.

Niners coach Mike Nolan picked O'Sullivan to start to get the chance to see his newest quarterback play after having already coached Smith and Hill. Nolan couldn't have liked what he saw.

O'Sullivan, who has never started a game in the NFL, struggled to move the ball on two drives against Oakland's starting defense. His third drive ended on an ill-advised throw downfield that was intercepted by Stanford Routt. O'Sullivan then fumbled while scrambling on the next drive. He finished 5-for-8 for 71 yards.

Smith was forced to compete for the starting job after a difficult 2007 season in which he struggled early, then injured his shoulder, and finally had a public blowout with Nolan. He threw incompletions on his first three attempts before leading the Niners to a 22-yard field goal by Joe Nedney at the end of the half. Smith finished 5-for-9 for 51 yards.

Johnnie Lee Higgins, who averaged only 5.2 yards per punt return as a rookie last year, opened the scoring with a 53-yard punt return late in the first half for Oakland.

Notes:@ Frank Gore played only one series for the Niners, gaining 6 yards on two carries. ... Raiders kicker Sebastian Janikowski missed the game with an undisclosed injury. Oakland signed Aaron Elling to take his place for the game. ... WRs Isaac Bruce, Bryant Johnson and Ashley Lelie missed the game for the Niners.