"Hurt his hip flexor," Babcock said. "He's out."
Asked during a television interview if Howard is out for a while, Babcock replied, "I don't know. You know how it is here."
"I don't know how any of this works," he said. "I just know that Mrazek's starting [Sunday]."
Howard is one of three goalies selected for the U.S. roster for the 2014 Sochi Olympics.
Asked if Alfredsson's injury was unexpected, Babcock responded, "I'm getting to expect it, right? I come in every day and someone's not playing. Bottom line is, the guys that dressed played hard."