Linus Ullmark is considered week-to-week after sustaining a lower-body injury on Tuesday, Sabres interim head coach Don Granato announced Friday.
Ullmark previously missed 15 games with a lower-body injury in February and March. The Sabres have 13 games remaining this season, which concludes May 8.
"Right now, it's week-to-week and we don't have many weeks left," Granato said. "So, that one's a little touchy."
Ullmark is 9-6-3 with a .917 save percentage in 20 games this season. He is scheduled to become an unrestricted free agent this summer, though general manager Kevyn Adams said Monday that the team hopes to keep him in the fold moving forward.
Dustin Tokarski made his fifth start of the season on Thursday in Ullmark's absence, stopping 27 shots against Washington to earn his first NHL victory since 2015. Michael Houser, who has not played in the NHL, served as Tokarski's backup.
Granato said the team is looking to integrate goaltending prospect Ukko-Pekka Luukkonen into the NHL roster but is still determining a timeline for his potential recall. Luukkonen has been dealing with a minor lower-body injury that forced him to miss Rochester's game on Wednesday.
Luukkonen, a second-round pick in 2017, is 7-5-3 in 14 games with Rochester this season.
"Today's an important day to determine when he'll be integrated with us," Granato said.
The Sabres are also without Carter Hutton, who has been out since March 24 with a lower-body injury. Granato said Hutton has resumed skating on his own but there is no timetable for his return.
Granato also provided injury updates on forwards Kyle Okposo and Riley Sheahan, both of whom missed practice on Friday. Sheahan is considered day-to-day after sustaining an upper-body injury against Boston on Tuesday. Okposo is still being evaluated by doctors after he was hit in the head with a shot on Thursday.
Lines at Friday's practice
53 Jeff Skinner - 23 Sam Reinhart - 68 Victor Olofsson
96 Anders Bjork - 24 Dylan Cozens - 25 Arttu Ruotsalainen
74 Rasmus Asplund - 37 Casey Mittelstadt - 72 Tage Thompson
13 Tobias Rieder - 20 Cody Eakin - 38 Jean-Sebastien Dea / 49 C.J. Smith
26 Rasmus Dahlin - 10 Henri Jokiharju
78 Jacob Bryson - 55 Rasmus Ristolainen
44 Matt Irwin / 88 Brandon Davidson - 33 Colin Miller
The Sabres host the Penguins for the first of back-to-back games at KeyBank Center on Saturday afternoon. The two teams will co-host a joint "Pride Game" in celebration of the LGBTQ+ community.
The game will be broadcast nationally on NBC.
"I think it's awesome," Granato said. … "It makes it a bigger deal and it makes it a lot of fun that the other team, as we know, they're engaged in that initiative and inclusion in our game. I'm looking forward to it."
The game begins at 3 p.m.