In the immediate aftermath of the Bruins’ 4-2 loss to the St. Louis Blues on Tuesday, it was clear that Coach Bruce Cassidy did not like a lot of things he’d just seen from his team.

A night’s sleep did not alter that much.

During a fairly intense Garden practice for a late season session on a day between games, Cassidy sprinkled a few expletives in his pointed on-ice criticisms as he tries to right his injury-plagued team that has now lost three of four games.

And while Cassidy wasn’t dumping Tuesday’s loss and the recent slide on Trent Frederic, it doesn’t appear he’s going to let the winger’s costly, undisciplined penalty in the second period slide. In Wednesday’s practice, Tomas Nosek replaced Frederic on the third line with Charlie Coyle and Craig Smith.

With the postseason looming, Cassidy is using Frederic’s mistake as a teachable moment.

“We have goals coming forward here. First one is to get in the playoffs, punch our ticket. We’re very close to that. We’re not there yet. Then we know the brand of hockey to expect once you get in, and you just have to have a certain amount of discipline to play, not take yourself out of the game individually or as a team. And that’s where Freddy has to learn,” said Cassidy.

On the penalty in question, Frederic got into some postwhistle pushing and shoving with Vladimir Tarasenko before Colton Parayko came over to assist the Blues’ star. In the scrum, Frederic appeared to pop off Parayko’s helmet, which is an automatic penalty, but it was announced as a roughing penalty taken against Tarasenko. Frederic said that, in the midst of the scrum, he was just trying to give back was he was getting and didn’t intentionally try to knock the helmet off.

But while Frederic wasn’t exactly sure what put it over the edge to give him the two-minute minor, he took responsibility for picking the wrong time to be edgy in the first place.

“What you can learn from it is we had momentum going, 2-1 us, we were probably dominating for about 15 minutes. So we didn’t real need anything there. It just wasn’t necessary. There was no benefit,” said Frederic on Wednesday. “It wasn’t my best moment as a Bruin. But I can learn from it and just be better, be smarter.”

One bad penalty does not tell the whole story of what’s been ailing this team. Injuries, of course, have been brutal. They started Tuesday’s game without Matt Grzelcyk, David Pastrnak and Hampus Lindholm and then lost Brandon Carlo midway through the first period.

But no matter who is in the lineup, Cassidy said the Bruins need to manage pucks much better. The Blues’ third and fourth goals were results of turnovers near the offensive blue line by Brad Marchand and Charlie Coyle. And when battles are lost, they need to do a better job at recovering and defending than they have been.

“Some bad habits are creeping in. They’re hard to break sometimes,” said Cassidy. “There’s certainly no need to panic because we haven’t been on the run we were in March and February. But we have to address it and get back to playing good hockey. Let’s hope that starts (Thursday). If not, then we’ll focus on Saturday.

NO CARLO DIAGNOSIS: Carlo did not practice Wednesday and Cassidy did not want to venture any kind of guess as to the length of time the defenseman will be out of the lineup until he’s heard from team doctors.

“He’s got to get further evaluation before I can tell you he’s week to week or day to day or in or out,” said Cassidy.

What exactly is wrong with Carlo is not clear, but he has a history of concussions and he appeared to be shaken up on a borderline Lars Eller hit in Washington on Sunday.

Neither Lindholm (knee) nor Pastrnak (core) practiced Wednesday, and they will miss Thursday’s game against Ottawa. Cassidy did not rule them out beyond that.

The good news on the injury front is that Grzelcyk, who appeared to have suffered a recurrence of shoulder issues when he left Sunday’s game in Washington in the first period, participated fully in practice and Cassidy was “cautiously optimistic” he’d be able to play against Ottawa.

JESPER FRODEN was recalled from Providence of the American Hockey League, and he skated on a line with Taylor Hall and Erik Haula, while Marc McLaughlin dropped down to center a fourth line between Nick Foligno and Curtis Lazar.

Patrice Bergeron (maintenance) did not practice. He’s expected to play Thursday.

JOHNNY BEECHER, the Bruins’ 2019 first-round draft pick (30th overall), has left Michigan after his junior season and signed an amateur tryout contract with the Providence Bruins while he and Boston finalize his entry level contract, said GM Don Sweeney in a statement.

The 6-foot-3, 209-pound Beecher has speed to go with that size, but on a talent-laden Wolverine team, he did not have a lot of production. In 81 collegiate games, he had 19 goals and 20 assists. A good defensive player, it will be interesting to see what kind of pro player he becomes.