Alameda, CA (SportsNetwork.com) - The Oakland Raiders made it official Thursday and named Jack Del Rio as their new head coach.

Terms of the deal were not disclosed, but NFL.com on Wednesday said it would be a four-year contract for the former Jacksonville Jaguars head coach.

"After a thorough interview and evaluation process, we are excited to announce Jack Del Rio as the head coach of the Oakland Raiders," said owner Mark Davis. "I have no doubt that he will make a significant impact and help reach the goal of everyone in this building, which is to win championships."

Del Rio will join the Raiders after three seasons as defensive coordinator for AFC West rival Denver. The Broncos had the NFL's third-ranked defense during the 2014 regular season.

The 51-year-old was Jacksonville's head coach from 2003 until he was fired in 2011 near the end of his ninth season. The Jaguars were 68-71 under Del Rio, making the playoffs twice.

The Raiders haven't been to the playoffs since losing to Tampa Bay in the Super Bowl after the 2002 season, and haven't had a winning record in the 12 years since that run.

"Jack Del Rio brings a strong leadership presence to this organization," said Raiders general manager Reggie McKenzie. "He has developed an excellent reputation as a coach in this league and we are happy that he is a Raider."

Oakland was 3-13 in 2014 under Dennis Allen and Tony Sparano. Allen, who also joined the Raiders after serving as defensive coordinator with the Broncos, was fired after an 0-4 start. Sparano, who was interviewed for the full-time post, was 3-9 over the final 12 games.

Del Rio, raised in nearby Hayward, California, was a linebacker for 11 years in the NFL from 1985-95, then began his coaching career with the Saints as assistant strength coach in 1997.

After two years with New Orleans, the second as linebackers coach, Del Rio moved on to Baltimore and was the linebackers coach with the Ravens for three years. After a one-year stint as defensive coordinator with Carolina in 2002, he took over as head coach in Jacksonville.