When Rangers center Brian Boyle finished his extra conditioning skate yesterday morning, he sat at his locker and slouched. A sympathetic onlooker said sorry, and Boyle shook his head, eyes down, wet black hair hanging over his face. “Don’t say sorry,” Boyle said. “It’s nobody’s fault but mine.” Boyle was the first big-time casualty of coach John Tortorella’s decision to give no quarter in regard to playing time. He made Boyle a healthy scratch for last night’s 4-1 win over the Islanders at the Garden. When Tortorella was asked before the game what he wanted for Boyle in watching from the press box, he was nothing if not sharp. “To be miserable,” Tortorella said. “And to hope that he never puts me in this type of decision again.” It might be tough for Boyle to crack back into the lineup with the good play of rookies Chris Kreider and J.T. Miller, but that is not deterring him from trying. “Not enough confidence, and it’s affected my whole game,” Boyle said. “I need to find a way to get back to playing well. Because I know I can, because I have.” * Captain Ryan Callahan returned from a partially dislocated left shoulder and played his regular assertive game, getting 19:22 of ice time and registering two shots, four hits and two blocks. He had missed the past three games, and came back earlier than scheduled.