Dr. Michele Morgan migrated last fall from Detroit to Phoenix, taking a job as a psychiatrist. She expected her husband, Sam Kirkland, to soon join her, since he was accepting an early retirement package from his employer, General Motors. But he cannot move, he says, because he has not been able to sell the four-bedroom family home.

“As things now stand,” said Mr. Kirkland, who is 51 and intends to seek work in Phoenix, if he ever gets there, “my wife might decide to give up her job in Phoenix and come back to Detroit for a while, until we can sell the house.”

The rapid decline in housing prices is distorting the normal workings of the American labor market. Mobility opens up job opportunities, allowing workers to go where they are most needed. When housing is not an obstacle, more than five million men and women, nearly 4 percent of the nation’s work force, move annually from one place to another  to a new job after a layoff, or to higher-paying work, or to the next rung in a career, often the goal of a corporate transfer. Or people seek, as in Dr. Morgan’s case, an escape from harsh northern winters.

Now that mobility is increasingly restricted. Unable to sell their homes easily and move on, tens of thousands of people like Mr. Kirkland and Dr. Morgan are making the labor force less flexible just as a weakening economy puts pressure on workers to move to wherever companies are still hiring.