After a three-week vacation, Governor Deval Patrick returns to the Statehouse to the widespread belief that he will announce his support for casino gambling within days.

The only question in many people’s minds is what form that approval will take. Speculation has centered on as many as three casinos: one in Boston, another in Southeastern Massachusetts for the Mashpee Wampanoag tribe, and a third in Western Massachusetts. Any casino proposal would be subject to legislative approval, a high hurdle in the state House of Representatives.

Patrick’s aides have described his summer sojourn as a working vacation, much of it spent at his second home in the Berkshires. They say he has been in daily contact with advisers. He has also been reviewing briefing materials that were compiled this summer by his gaming study group.

Patrick has kept his views on gambling closely guarded, leading many to believe he has shared them only with his inner circle of top advisers.