Khalil Mack signs four-year deal with Oakland Raiders

The Oakland Raiders have signed linebacker Khalil Mack to a standard four-year contract with a fifth-year option while the pact is fully guaranteed.

The financial terms of the deal have yet to be disclosed as the Raiders became the second team to get their first-round selection under contract.

Mack was the fifth overall selection in the NFL Draft 2014 and has been touted as an immediate contributor in terms of improving Oakland's defense.

He becomes the second rookie to sign a contract after the Chicago Bears announced a deal on Wednesday for cornerback Kyle Fuller.