Hart did not return after suffering a "mid-body" injury early in the game.
The Philadelphia Flyers lost more than just a game Wednesday night.
In their 5-2 loss to the Buffalo Sabres at Wells Fargo Center, the Flyers also spent much of the night without their star goaltender.
Carter Hart exited the game in the first period with what the Flyers are calling a "mid-body" injury. The injury occurred early in the frame when Hart extended his right leg to make a pad save. He stayed in the game after a quick visit from a Flyers trainer, but exited for good after allowing the Sabres' second goal of the night.
He also let a laser from Jeff Skinner get past him, but the goal was called back following a successful offside challenge by Flyers head coach John Tortorella.
After struggling in his first two appearances of the season, Sam Ersson stopped seven of nine Sabres shots in relief of Hart.
Joel Farabee scored the game's first goal just 55 seconds into the opening stanza. Farabee tried passing the puck to Bobby Brink on an odd-man rush, but his feed deflected off of Sabres defenseman Henri Jokiharju's stick and fluttered into the net over goaltender Ukko-Pekka Luukkonen's glove.
It didn't take the Sabres long to respond, though. Casey Mittelstadt evened the score less than two minutes later off a quick feed from JJ Peterka, then Brandon Biro netted his first NHL goal with a greasy goal on the doorstep after receiving a behind-the-net pass from Tage Thompson.
Biro later scored the empty-netter in the game's dying minutes.
Cam Atkinson potted his sixth goal of the year to tie the game at 2-2. After some nice work by Travis Sanheim and Cam York to deny a Sabres zone entry, Atkinson pulled off a one-handed redirection on a weak shot from Sanheim on the rush.
Sanheim was outstanding throughout the contest. He picked up the primary assists on both Flyers goals and generated several quality scoring chances, including a shorthanded opportunity that nearly gave the Flyers the lead late in the middle period.
Unfortunately, Sanheim's strong night wasn't enough to guide the Flyers to a comeback in their final game of their homestand. The Sabres pulled away in the final frame with goals from Owen Power, Thompson and Biro accompanied by some massive stops by Luukkonen, who finished the night with 38 saves on 40 shots.
After a strong start to the season, the Flyers have now lost three straight games and five of their last six.
The Flyers will return to action Friday against this same Sabres team at KeyBank Center in Buffalo. The puck drops at 7 p.m. ET.