ALAMEDA, Calif. -- Bobby Johnson was hired to be the Oakland Raiders' tight end coach, but it’s his background as an offensive line assistant that made him an attractive option for Oakland head coach Jack Del Rio.

For more than a decade the Raiders have been searching for and trying to develop a blocking tight end. Given the state of their offensive line, that’s become even more important.

David Ausberry was supposed to fit that role and is the team’s most accomplished blocker as a tight end, but the 2011 seventh-round draft pick has missed 26 games over the past two seasons because of injuries. He’s also coming off knee surgery.

Brian Leonhardt tried to fill the gap in 2014 but ended his season on injured reserve due to a concussion.

Oakland’s best tight end in terms of receiving is Mychal Rivera. Rivera has 96 receptions and eight touchdowns in two seasons and proved to be one of quarterback Derek Carr’s most reliable downfield threats in 2014. But while Rivera has improved as a blocker, the Raiders would prefer to find another option to free up Rivera more in the passing game.

Normally a blocking tight end wouldn’t be high on the priority list for any NFL team, but Oakland has struggled to run the ball with any kind of consistency and needed to keep its tight ends in to assist with the blocking. The results were mediocre at best.

That’s where Johnson will come in.

He was Detroit’s tight ends coach in 2013 before being moved to offensive line assistant when Jim Caldwell was hired as head coach.

The Lions did not get the expected production out of their trio of tight ends (Eric Ebron, Brandon Pettigrew and Joseph Fauria) that they had hoped for in 2014, but all three stood out with their blocking, which helped Detroit overcome some of its own inconsistencies.

Johnson’s main priority in Oakland will be trying to get the same or more out of the Raiders tight ends. While Rivera’s job is safe -- he’s the clear-cut starter -- the team doesn’t have much depth behind him. Oakland will look to improve that either through the draft or free agency.

One option could Denver’s Julius Thomas, who is scheduled to hit the free-agent market this offseason. Thomas grew up a fan of the Raiders and has already gone on record saying Oakland is a team he would definitely consider playing for.

Either way, look for Johnson to be very hands-on with whomever the Raiders bring in.