Polk, the second-leading rusher in program history, ran for 1,488 yards and 12 touchdowns this season for Washington. He is projected by many as a second-round pick.
"I'm ready to move on to the next phase of my life," Polk said. "I may not be the biggest or the fastest but I will do whatever it takes to win."
During Polk's career, the Huskies rose from a winless season to back-to-back bowl appearances. In his last game, he carried 30 times for 147 yards and a touchdown in Washington's 67-56 shootout loss to Baylor in the Valero Alamo Bowl.
"It was a roller coaster to go from 0-12 to back-to-back bowl games," he said of the experience.
Polk rushed for 4,049 yards on 799 carries over 40 games at Washington. He ends his college career just 57 yards shy of Napoleon Kaufman's school rushing record. He ran for 1,113 yards as a redshirt freshman in 2009 and 1,415 yards in 2010.
"Chris had a terrific career at Washington and deserves the opportunity to move on to the next level," Huskies coach Steve Sarkisian said in a prepared statement. "We wish him nothing but the best in what I'm sure will be a great professional career."
Joe Schad is a college football reporter for ESPN.