Raiders big men left to answer: Where's the beef?

ALAMEDA -- The men Khalil Mack once called "meat and potatoes" have been reduced to gristle and mash.

That's the pre-season overreaction anyway, with the run defense in question as the Raider host the Seattle Seahawks Thursday night at the Coliseum in their final tune-up before the regular season begins on Sept. 11.With big backs such as Eddie Lacy, DeMarco Murray and Derrick Henry gashing the Raiders up the middle for the last two weeks, beefy defensive tackles Justin Ellis and Dan Williams -- meat and potatoes -- are feeling some heat.Neither player is overly concerned, nor is coach Jack Del Rio."You get these opportunities in the preseason to kind of tighten things up," Del Rio said. "I…