Former Stanford law professor and two-time California congressman Tom Campbell is reportedly dropping out of the California governor’s race to run for the U.S. Senate.

Campbell previously represented California’s 12th district — which includes Stanford — and, later, its 15th district. Campbell is a Republican.

According to a supporter e-mail obtained by The San Jose Mercury News, Campell is set to announce a “new venture” Thursday, confirmed by campaign sources to be a run against Democratic Senator Barbara Boxer.

The departure of Campbell from the governor’s race leaves former eBay executive Meg Whitman and state Insurance Commissioner Steve Poizner to contest the GOP gubernatorial primary.

The Republican Senate primary features former Hewlett-Packard CEO Carly Fiorina and state assembly member Chuck DeVore.

Campbell has run twice for the U.S. Senate unsuccessfully.