He played in Major League Baseball (MLB) for the Colorado Rockies and San Francisco Giants in 2014 and 2015.

He never appeared in an MLB game for the Angels, and was purchased by the San Francisco Giants (the team who originally drafted him in the first round in 2007) on March 17, 2015.

On November 10, 2015, Williams signed a minor league contract with the Colorado Rockies organization.

He split the 2016 campaign between the Double–A Hartford Yard Goats and Triple–A Albuquerque Isotopes, hitting .199/.265/.263 with one home run and 20 RBI across 68 total games.

He played in 26 games split between Altoona and Indianapolis, accumulating a .221/.277/.314 batting line with two home runs and 10 RBI.