Celtics president of basketball operations Danny Ainge recently had good reason to claim that he doesn’t have a list of priorities heading into what will be one of his busiest offseasons in the last 10 years. “Every player is priority,” Ainge said. Consider, for example, that half of the 25-57 roster from this just-completed season could be gone by the time training camp opens in October for the 2014-15 campaign. Consider that Avery Bradley — one of the C’s brightest hopes in the last four seasons — could easily join the departed. In most years, unrestricted free agents are a good bet to return to the team that holds their matching rights. But when Bradley and his camp broke off extension talks with the Celtics over the winter despite the fact that the sides weren’t far apart, the guard may also have lost out on his best-case money scenario for next season. Bradley’s ongoing brittleness considered, the C’s are unlikely to return to the four-year, $24 million extension that was previously offered. The injury issue may also limit what he finds on the market this summer. Chronic ankle trouble limited Bradley to a 60-game season. He has never had a fully healthy NBA season, a circumstance that won’t give him much leverage. Bradley’s most durable regular season came in 2011-12, when he played in 64 games, and he excelled in 10 playoff games before chronic shoulder trouble forced him out. On the other hand, Bradley clearly improved his lot as a shooting guard. He closed 2013-14 by averaging 22.4 points over his last five games. He shot 53 percent (18-for-34) from 3-point range over that stretch.