The Mets traded Billy Wagner to the Boston Red Sox on Tuesday afternoon, consummating the deal just before his waiver claim expired at 1:30 p.m. To join the Red Sox, Wagner changed his mind and waived his no-trade clause. Just Monday, Wagner said he did not expect to be traded unless ?something changes with Boston.? The Red Sox assured Wagner that they would decline his $8 million team option for 2010, thus making him a free agent. But they remained steadfast on another front, refusing to promise that they would not offer him arbitration. Wagner projects as a Type A free agent, and teams that lose Type A free agents net two high draft picks. The Mets will receive two minor leaguers, but they are happier about shedding the approximately $3.2 million owed him.