Ullmark will defend the cage versus Buffalo on Saturday, Joe Haggerty of BostonHockeyNow.com reports.
Ullmark was given the starting nod for the first of the Bruins' upcoming back-to-back games. Through his three December appearances, the 28-year-old has posted a 2-1-0 record with a 2.02 GAA and a .946 save percentage. He will look to bounce back from the loss handed to him by the Islanders in his last outing.