It was Ullmark's eighth game since he returned after a break from the NHL for personal reasons.
His first loss was to Montreal in regulation; otherwise he had five wins and two overtime losses.
In this game he allowed a goal in each period. Ottawa led 2–1, but the home team came back to win 3–2. Ivan Demidov's decisive goal came 12:40 into the third period.
"It feels like I should take it, but the puck bounced their way," Ullmark said.
In the hunt for the playoffs, Ottawa is five points ahead of Boston and six points ahead of Detroit in the wild-card race.
