Ullmark stopped both shots he faced over 4:46 of game time in Sunday's 5-4 loss to the Avalanche.
Ullmark was called upon twice to take the crease while Anton Forsberg dealt with a skate issue in the second period. This will count as Ullmark's fourth appearance of the season. The 31-year-old is expected to resume his role as the Senators' No. 1 goalie after dealing with a muscle strain for a week. He'll likely get the nod at home Tuesday versus the Blues.