The Oakland Raiders signed former San Francisco 49ers linebacker Aldon Smith on Friday in an effort to bolster their defensive front ahead of the 2015 season.

San Francisco released Smith in early August after he was charged with driving under the influence and vandalism in an hit-and-run incident.

Smith practiced with the team on Friday, according to Ed Werder of ESPN who cites a source that says he impressed the coaching staff and the Raiders plan on having him in Week 1 unless the league intervenes.

The standout pass-rusher has yet to be disciplined by the NFL for his latest run-in with the law - his fifth in the past three years - and would be eligible to play until punishment is issued by the league office.

Misdemeanor charges stemming from the arrest were officially filed by the Santa Clara County DA shortly after Smith joined the Raiders on Friday, with his arraignment scheduled for Oct. 6, according to Matt Keller of ABC7 News.

Smith is joining the Raiders on a one-year contract worth up to $8 million with roster incentives, Bleacher Report's Jason Cole reports.

If he avoids a season-long absence, as the Raiders appear to be counting on given the one-year agreement, Smith would combine with second-year defensive end Khalil Mack to give Oakland one of the league's most explosive pass-rush tandems.

"We are confident that the Raiders provide an environment where Aldon can thrive through the support, structure and leadership within the building," general manager Reggie McKenzie said in the team's official announcement. "We are excited to have Aldon here in the Raiders family."

The former first-round pick recorded 44 sacks in 50 regular-season games with the 49ers, highlighted by a 2012 sophomore season in which his 19.5 sacks earned him both a Pro Bowl nod and first-team All-Pro honors.