The last time Michael Ryder set foot in the Garden on a game night, it was for Game 6 of the 2011 Stanley Cup finals, he was wearing a Bruins sweater and he was two games away from reaching the pinnacle of his career. But last night, Ryder seemed to be still wrapping his mind around a different walk down memory lane — one that was thrust upon him when he was traded from the Dallas Stars to the Montreal Canadiens, his original NHL team, last week. “Everything’s been happening pretty fast the past three or four days. It’s been pretty interesting,” said Ryder, who picked up an assist in the Canadiens’ 4-3 win last night. “It’s the first time getting traded for me, going back to Montreal, playing in Toronto, back to Montreal (for Saturday’s game) and then playing in Boston. It’s good to be back on the other side again, but it is what is.” With the Bruins trying to find the right mix on the Rich Peverley-Chris Kelly line, there was rampant speculation that Ryder could be a trade target for the B’s to fill out his old line. Ryder was oblivious to that discussion, but he didn’t think it was going to happen anyway. “If they wanted to keep me, they probably would have tried to sign me after that year,” Ryder said. “But sometimes that happens. It’s part of the game and you have to move on. I liked it in Dallas. I had a good year there last year and this year I got traded. But it’s part of the business. It happens, and I’m excited to be back in Montreal and helping the team.” Having been given the cold shoulder on the way out the door in Montreal five seasons ago, Ryder said he could read the signals that the Bruins weren’t going to have him back. Was that upsetting to him?