On 12 October 2010, just prior to the commencement of the 2010–11 season, Greiss was put on waivers by San Jose, eventually clearing and reporting to Worcester of the AHL. Greiss' demotion was in large part due to the off-season signings of Finnish goaltenders Antero Niittymäki and Antti Niemi. Nine days later, after failing to see any gameplay as Worcester's third-string goaltender, he was reassigned to Brynäs IF in the Swedish Elitserien to provide him regular playing time. In April 2011, Greiss was recalled from Brynäs to San Jose for the team's run in the 2011 Stanley Cup playoffs. He later re-signed with the Sharks on 7 July.