Dr. Venkman (g, 5, Ghostzapper--Theory of Change, by Archarcharch), winner of the GII San Diego Handicap at Del Mar 13 months ago, returned to the scene of his biggest career triumph to add the GII Pat O'Brien Stakes Saturday. The $250,000 Pat O'Brien, run at seven furlongs, offers a 'Win and You're In' berth to the GI Breeders' Cup Dirt Mile, to be held over this surface Nov. 1. Despite a field of veterans, the Pat O'Brien was not without incident. Two of the six horses--Stronghold (Ghostzapper) and Spirit of...