In their five-game defeat of the Minnesota Wild in the first round, the Blues allowed eight goals (1.60 per game), which is in line with what they allowed in the final 21 regular-season games after the Shattenkirk trade (40 goals, 1.90 per game).
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In their first 61 games the Blues allowed 176 goals (2.88 per game), eighth-most in the NHL.
Adjusting to the new system installed by coach Mike Yeo after he replaced Ken Hitchcock on Feb. 1 played a role. So did the return of defenseman Robert Bortuzzo in Game 2 against the Wild after missing six games because of an upper-body injury.
"I don't want to say that our identity has changed back there but obviously if you take a guy like [Shattenkirk] out and replace him with a guy like Bortuzzo, then they're different types of players," Yeo said. "We've got a big group, we've got a physical group. We've got a group that's going to compete and make it tough on the other team. But our defensive game relies far more than just on our defensemen. I think that from that point on [after the Shattenkirk trade], we were in must-win mode, and when you get in there the focus on all the details of our game has been there.
"And the forwards, it's their job to make sure they're helping out as well in terms of how we play with the puck and how we play without the puck. If we're doing the right things, then they should help make the defensemen play a better game."