 The majority ownership group of the Boston Celtics is planning to make the franchise available for sale. Celtics announcing yesterday that the managing board of the ownership group expects to sell a majority interest in the team either this year or early next year. Wick Grosbeck is expected to remain as the governor of the team until the second closing in 2028, according to ESPN. Boston has also agreed to a four-year, $125.9 million contract extension with guard Derek White.