The last time the Bruins played the Pittsburgh Penguins, Milan Lucic was not invited to the festivities.

Suffering through the worst slump of his career, Lucic’s game was at the nadir of his still young career. His confidence was in such a sorry state that it was taking a Herculean effort for him just to be able to chip the puck out of his own zone.

And finally, coach Claude Julien had reached a point he didn’t want to get to with Lucic. Lucic had been bumped off the top line, he’d played a little bit on the fourth line, and nothing seemed to give his game a spark. So Julien had to make him a healthy scratch when the Bruins played the streaking Penguins on April 20, the day after the game was originally scheduled because of the hunt for the suspected Boston Marathon bombers.

Big-game players — and Lucic can rightly think of himself as one — want to play in games like that. Instead, he had to watch from the Garden’s ninth floor with the rest of the scratches.

“It made it more difficult because you’re playing the best team in the East at the time, and they were still on that winning streak. Those are the games you want to play in, the big ones. Being out of the lineup sucks in itself, but being out of the lineup in a game like that makes it even worse,” Lucic said yesterday after the Bruins’ first practice in preparation for Saturday’s opener of the Eastern Conference finals against the Pens.

“I felt like my approach to it was going to be one of trying to turn it into a positive instead of a negative. Because I felt like it was a special group here and I didn’t want it to end. If it ended early, it would have been a complete disaster of a year. But I just felt like that was an opportunity to turn things around and have a strong finish and start feeling good and get my game back up to where I wanted it to be in order to feel well heading into the playoffs.”

That healthy scratch was just 51⁄2 weeks ago, but it seems like ancient history when you see Lucic playing now. He is once again the catalyst that helps drive the Bruins’ engine. He has 10 points (three goals, seven assists) through the first two rounds of the playoffs, and is a plus-9 (tied for second in the league with his center David Krejci, who both trail league leader Nathan Horton’s plus-14). Perhaps the most telling Lucic stat is his 55 hits, fourth-most in the league.

It was a step-by-step process as he played a little better in the final week of the regular season.

“You can’t go from 0-to-60 in one game,” said Julien after Lucic’s promising return game on April 21 against Florida.