Kevin Hoffman / USA Today Sports
The 24-year-old goaltender registered a career-high 44 saves to help the Sabres beat the Columbus Blue Jackets and snap a five-game losing streak (0-4-1).
Ullmark had previously made 42 saves in games played back in 2015-16.
Drafted 163rd overall in 2012, Ullmark has spent the majority of his pro career in the AHL after making the move from Sweden.
He may, however, be in line for more starts moving forward if the Sabres decide to trade a goalie prior to the deadline.