BALTIMORE - Washington Redskins left tackle Trent Williams agreed to terms Saturday on a new five-year contract that comes with $32 million in guaranteed money.

Williams' agent, Vincent Taylor, said Williams will receive an $8.5 million signing bonus. The sixth-year veteran will receive an average salary of $13.2 million, and the $66 million deal provides for an additional $11.25 million in guaranteed money if he gets injured.

Taylor said the contract is the largest in NFL history for an offensive tackle.

The 27-year-old Williams was selected to the Pro Bowl in each of the past three seasons. He was drafted fourth overall in 2010 out of Oklahoma.

Taylor said Redskins president Bruce Allen, general manager Scot McCloughan and vice-president of football administration Eric Schaffer helped make the deal happen.

"They were an integral part in getting it done," Taylor said, "and a pleasure to work with."

Williams announced the deal through Twitter before the Redskins faced the Baltimore Ravens on Saturday night. He tweeted: "Happy to announce I will be a redskin for the next 5 years. This is a dream come true."

The 6-foot-5, 337-pound Williams started at left tackle against the Ravens.

Williams did not play in Washington's second preseason game; coach Jay Gruden said the lineman had an injured right foot.