Maliek Collins among X-factors counted on to improve Raiders defense

The Raiders invested significant funds and a first-round NFL draft pick in defense this offseason, hoping to add depth and talent to a unit that has been completely overhauled during this Jon Gruden era.It has been a slow build, with additions coming largely through the draft. Gruden and GM Mike Mayock pushed the accelerator down a smidge in free agency to shore up the middle of this unit with talent vital in the modern NFL.That includes interior pressure, fast, sideline-to sideline linebackers and a safety pairing that is as versatile and it is aggressive.