ALAMEDA, Calif. -- The Raiders announced Thursday that they signed third-round draft pick Gabe Jackson, a guard who is vying for Khalif Barnes' starting job on the left side and is expected to add punch to the power running game.

A powerful interior blocker, Jackson was a first-team All-America selection who had 52 starts for Mississippi State in the Southeastern Conference, home of the toughest defensive linemen in college football.

He was a three-year starter and the son of a high school coach and, according to NFLDraftScout.com, has more than enough size, strength and ability to be a top-notch player.

The concern going into the draft was that he did not perform at that high level consistently. Per the draft scouting report, he "has tantalizing balance of overall power, agility and great feet but sometimes misses things he should pick up, which could be dangerous for NFL QBs."

Jackson is the final of the team's eight draft picks from the 2014 NFL Draft to sign a rookie contract.

Jackson, rated No. 73rd overall and the fourth best guard in the draft, was selected 81st overall by the Raiders. In his senior year, he was awarded the Cornerly Trophy as the top collegiate player in the state of Mississippi and also claimed the Kent Hull Award as the top offensive lineman in Mississippi.

The Liberty, Miss., native played on both sides of the ball at Amite County High School for his father, Charles Jackson, who was the head coach.