Torey Krug has not scored a goal since Dec. 8 and, in that 11-game stretch, he has posted just two assists. But the 22-year-old defenseman was under no illusions when he came into his first full NHL season. Though he exploded onto the scene in the playoffs last year, he’s still a rookie and wasn’t expecting his existence to be always charmed. “I knew there were going to be ups and downs,” Krug said before the Bruins beat Nashville, 3-2, in overtime last night. “Whether you’re a 20-year player or a first-year player, there are going to be bad nights and it’s just about minimizing those.” He had a particularly rough night in Ottawa last Saturday when, in 19:10 of ice time, he was a minus-3 and coughed up the puck on Bobby Ryan’s game-winning goal. But with the way that the offensive-minded Krug plays, he’s learned to deal with those kinds of high profile mistakes and move on. “It’s something that I’ve actually prided myself on, forgetting the last play and coming out and making an even better play the next shift,” said Krug. “Watching my school (Michigan State) play football (on Wednesday) and the quarterback (Connor Cook) threw a big interception. Then the next drive, he’s throwing balls right down the middle and they score a touchdown. After the game, that’s exactly what he said. It’s about putting those things in the rearview mirror and moving on to the next play.” With the loss of Dennis Seidenberg, the spotlight is burning just a little more brightly on young defensemen like Krug, Matt Bartkowski and Dougie Hamilton, who returned to the lineup last night after missing three weeks with a leg injury. No one expects any of those players to fill the role of Seidenberg, least of all the under-sized Krug. While acknowledging some struggles of the young defensemen, coach Claude Julien said he was pleased with their overall progression.