BUFFALO—Casey Mittelstadt has played against the Sabres a couple of times since he was traded from Buffalo two years ago at the trade deadline.

But Mittelstadt was expecting an atmosphere like he had never had the pleasure of experiencing when he was a Sabre for six-plus seasons after he was drafted eighth overall when the Bruins were set to take on the Sabres in their first foray into the post-season in 15 years.

“I’m expecting pretty much bedlam,” said Mittelstadt after the B’s morning skate prior Sunday’s Game 1. “I wouldn’t expect anything else. I’ve been to plenty of Bills games so I’m guess it’s going to be like that. It’ll be a blast. I’m excited I get to experience it.”

Mittelstadt got his only taste of the playoffs two years when he was traded to Colorado for current Sabre defenseman Bowen Byram and he played well for the Avs, posting 3-6-9 totals in 11 playoffs games. He was re-signed by the Av but was then dished at last year’s trade deadline for Charlie Coyle.

He was asked if it was “freaky” that he would find himself on the team against whom the Sabres would make their long-awaited re-entry into playoffs.

“A little less freaky than it would have been a couple of years ago,” said Mittelstadt. “But I think it’s cool. I loved my time here and I’ve probably cheered for them a bit. I’ve got a lot of friends, especially the staff who have been here for so long. I’m happy for them. But I’m on the other side of it now, so I’m definitely not cheering for them this series. It’s going to be fun. Obviously friendships go on hold and this is the most important thing right now, so let’s go have some fun.”

Mittelstadt’s first 18 games as a Bruin after the deadline last year left a lot to be desired. He had 4-2-6 totals and was minus-17 in 18 games.

There were some bumpy days early this season, too, under new coach Marco Sturm. But after he got a wake-up call scratch in Utah in October and was then moved from center to wing, Mittelstadt and his linemates Pavel Zacha and Viktor Arvidsson became the B’s most enduring and consistent line.

“I’m really pleased and happy the way it worked out,” said Sturm. “I remember him from the Buffalo days actually. I don’t know what happened after that. But there’s a lot of question marks, I feel like, could be from media or anywhere else, about his game and his performance. But I can tell you this. He’s been excellent with me. We maybe had a tough start but after that, he really took off. That line took off. So I’m really pleased with his game and where he’s at right now.”

Sturm allowing the line to grow together was helpful.

“When you come to a new place it can be hard. I’ve learned the challenges of that. The one thing that was nice for me this year, we’ve consistently played together since the first game of the year,” said Mittelstadt. “We’ve had time to build some chemistry and find that comfort. I was here for a long time and I didn’t know anything different and it’s hard to start over. It’s a very welcoming group (in Boston) and it’s been a lot of fun. I’m very happy with where I am.”

Mittelstadt finished with 15-27-42 and plus-12 in 71 games. And one of his goals came against his former team in one of the B’s biggest wins here, beating old teammate Rasmus Dahlin to a loose puck and knocking home the tying goal in the B’s 4-3 overtime win on March 25.

“We had pretty good banter during the game, to be honest. That one felt pretty good, honestly, on Ras,” said Mittelstadt with a grin. “A lot of years going back with him, we’ve had a lot of ridiculous arguments, so that one was fun for sure.”….

Sturm caused quite a stir in Western New York with his comments last week about how the B’s are bigger and stronger than the Sabres.

“A lot of teams are afraid of us,” he said at the time.

Sturm said it was only a logical assessment.

“Somebody had fun with it so I’m glad that happened,” said Sturm with his trademark wide smile. “At the end of the day, nobody’s looking as closely as I do. I watched the last four games when we played them and it was very clear to see. When we were on top of our game and when we are hard on pucks, when we are physical, we have a chance. And if we decide to play their way, we might as well stay at home. Because they’re that good. If you’re a Boston Bruin, you have to play that way. And if not, it’s going to be a long (game), because they skate well enough, they’re skilled enough, they have 108 points for a reason.”…

Buffalo coach Lindy Ruff knows the rivalry with the Bruins very well. He played in it during the 1980s and has coached in a couple of playoff series. The game isn’t quite as it used to be.

“Back then I had a hard time sleeping during the day when we knew that night was going to be one of those nights when you feared for your life sometimes,” said Ruff. ‘The game is different. Intimidation was a huge part of the game back then. Fighting was a big part of the game. Every team had four or five guys who could take care of almost anybody. Those series we had with the Bruins is a good example of it. But the game is in a lot better place. But we still saw a fight off the opening faceoff (Saturday in the Ottawa-Carolina series.) We’ve had a couple of games this year where we’ve had a number of fights inside the game. Playoffs is a time you can expect out of the normal. And there could be some of that.”

Ruff locked horns a few times with Bruins team president Cam Neely.

“I think I still try to avoid him, actually,” joked Ruff. “Cam’s a hell of a guy and all that was part of the game. I think my first fight with him, he was still in Vancouver at the time, maybe his first or second. I think he was one of the toughest two-way players to play the game.”