Boston Bruins return for Linus Ullmark, Mark Kastelic has been a bright spot for the Bruins

The Bruins have hit a rough patch since their win over the Colorado Avalanche, now on a three-game losing streak after a 5-2 loss to the Dallas Stars at TD Garden. Boston's middle lines are still trying to find some rhythm, and penalties have been a real issue during this stretch.

But despite the recent struggles, one positive has been the impact from the team's fourth-line center, Mark Kastelic, who's brought some serious physicality to the ice. Here's a look at some of the standout moments in hits and fights from the past week.

The Bruins faced off for the first time against the Utah Hockey Club at Delta Center last Saturday, though they left with just a point. During the second period, Kastelic delivered a heavy hit on Utah's Logan Cooley along the boards, sparking a reaction from Utah defenseman Robert Bortuzzo. The two clashed, wrestling each other down to the ice in a spirited exchange.

Kastelic wasn't done with the rough stuff. Later in the week, he squared off with Luke Schenn of the Nashville Predators, and it was all Kastelic in this one-sided fight. He's quickly proving to be one of Boston's best offseason pickups.

On Thursday night, Nikita Zadorov's physical game was on full display against Dallas. Although he needs to keep out of the penalty box, his presence was felt. Zadorov nailed Jamie Benn with a hard hit by the Bruins' bench and then leveled Evgenii Dadonov shortly after.

Boston may be looking for more consistency, but Kastelic and Zadorov are keeping the physical energy high, showing some bright spots in a challenging stretch.