Oklahoma quarterback Caleb Williams has started only one game, and just like that, he's The Associated Press' pick for the Big 12's top freshman of the first half of this season.

The 18-year-old's strong arm and swift legs have injected energy into a once-lagging offense that now is purring like usual under coach Lincoln Riley. Williams replaced preseason first-team All-American Spencer Rattler and rallied the Sooners to a 55-48 win over Texas on Oct. 9, then got his first start last Saturday against TCU and threw four touchdown passes and ran for another score in a 52-31 victory.

Riley was im...