CALGARY FLAMES VS BUFFALO SABRES 11/27/2019 LIVE 7:00 PM ET

Calgary Flames coach Bill Peters has more to worry about than just his team's 1-5-2 slump as it wraps up a four-game trip Wednesday in Buffalo.

The NHL is investigating claims Peters used racial slurs toward Akim Aliu when coaching the Nigerian-born forward in the American Hockey League a decade ago, when both were members of the Chicago Blackhawks' organization.

Aliu tweeted Monday that Peters "dropped the N bomb several times towards me in the dressing room in my rookie year because he didn't like my choice of music." Aliu said he "rebelled against him," and Peters then arranged for Aliu to be demoted to the ECHL.

Peters, who led the Flames to 50 wins last season in his first year with the team, was not made available to the media after Monday night's 3-2 overtime loss in Pittsburgh and was not at practice Tuesday. The team announced late Tuesday that associate coach Geoff Ward will replace Peters behind the bench vs. Buffalo.

The Flames have been outscored 28-9 in their past eight games and been shut out three times.

"I thought we had a good first period, took the lead, had some good chances," said Flames forward Johnny Gaudreau, who had an assist Monday to pass Lanny McDonald for 12th on the franchise points list with 407.

"They kind of pushed back and I think we pushed back at the end of the second into the third period. A lot of chances both ways ... just didn't get the extra point."

Things haven't been much better for the Sabres, who dropped to 2-8-2 in their past 12 games with a 5-2 loss Monday at Tampa Bay.

To make matters worse, defenseman Rasmus Dahlin, the first overall pick in the 2018 draft, suffered a concussion during a second-period power play after being hit with an elbow by Tampa Bay's Erik Cernak.

"Right now, we're just worried about Rasmus and getting him healthy, and hoping it's not a long-term injury," Sabres coach Ralph Krueger said.

Cernak, who didn't receive a penalty on the play, was scheduled to have a hearing with the NHL Department of Player Safety.

"Let's see what that judgment is because we're emotionally connected to that situation and as wrong as it feels that's always from a bias viewpoint, which is ours," Krueger said. "I know we have the vehicles that will analyze and take a look at it."

Jimmy Vesey scored his first goal for the Sabres -- and first since March 29 while with the New York Rangers -- on a breakaway early in the second period to give Buffalo a 2-1 lead.

"I thought it was a big goal at the time and definitely a good feeling for me," Vesey said.

Sam Reinhart also scored for the Sabres and Carter Hutton stopped 24 shots.

"We just need to start having a little bit more desperation in our game," said Sabres captain Jack Eichel, who extended his point streak to six games (six goals, five assists). "It just seems like we're accepting the fact that we're losing games right now, and it's not OK."