The move will see Westwood compete in The Players Championship at Sawgrass, which he did not contest this year due to scheduling complications, and attempt to qualify for the play-offs and FedEx Cup for the first time.
"I missed The Players Championship last year when watching it on television," Westwood said. "It was always a scheduling issue for me.
"Though the rules changed making it exempt from PGA Tour restrictions, I had already set my schedule for later in the year in Asia. I didn't want to break any of those commitments.
"It's a great event and one I've always enjoyed playing. It just felt right in Ryder Cup year to commit to a full programme in the United States.
"The FedEx Cup looked pretty good on TV this year. I thought it would be great to give it a go, having never taken part."
Westwood's first tournament in America will be the Accenture World Match Play in Arizona in February. He is obliged to play a minimum of 15 events in the United States.