Fenway Sports Group is not among the interested bidders for the Boston Celtics, multiple industry sources have confirmed to MassLive. The John-Henry led group, which also owns the Red Sox, Liverpool FC, the Pittsburgh Penguins in other sporting properties, was never seriously believed to be in the mix to buy the Celtics. On Monday, a story on NBC Sports’ Basketball Talk page characterized FSG as a group “expected to make a bid,” fueling rampant social media speculation. But nothing has changed since Red Sox president — and FSG CEO — Sam Kennedy threw cold water on the idea in September.