Tufts Health Plan is replacing its president and chief operating officer.[@@]

Many experts think of the nonprofit Waltham, Mass., carrier as being one of the country’s best providers of health coverage.

But the Tufts board says it has accepted the resignations of Nancy Leaming, the company’s current president, and Rich Hallworth, the company’s chief operating officer, in an effort to improve the company’s competitive position.

The board is naming James Roosevelt Jr., a grandson of Theodore Roosevelt and a former associate commissioner for retirement policy at the Social Security Administration, to take over as president of the company.

Roosevelt has been Tufts’ general counsel for the past 5 years.

“Jim has the full confidence of the Tufts Health Plan board of directors as he develops and implements an aggressive action plan to address declining membership,” Dave Scoon, chairman of the Tufts board, says in a statement about the personnel moves.