Sarandos said the final season would star Robin Wright in the lead.
While we don't know how Spacey's Frank will be written off the show, all signs seem to point to him being killed off-screen, something which is sure to have ramifications throughout the final season.
Filming is scheduled to resume early 2018.
The hit series, which focuses on political dealmaking in Washington, D.C., has provided 2,000 jobs to people in the Baltimore area where it is shot, Variety reported.
"The returning-series phenomenon is really exciting", Sarandos said, adding, "Last year, there was zero anticipation of "Stranger Things" before the show from the Duffer Brothers became a huge franchise.
All of Spacey's scenes were also erased from the upcoming film All the Money in the World, in light of the allegations made against Spacey.
Kevin Space and Robin Wright in "House of Cards".
The Metropolitan Police is investigating two claims of sexual assault against Spacey, while London's Old Vic theatre - where the star worked as artistic director from 2004-15 - says it has received 20 allegations of inappropriate behaviour against him. "We have also decided we will not be moving forward with the release of the film Gore, which was in post-production, starring and produced by Kevin Spacey", the statement read.
There's no word on when Season 6 will premiere but given the delay, it might not be complete until Fall or Winter 2018.
Spacey is now under criminal investigation in Nantucket, Mass., in connection with an allegation that he groped a 19-year-old man in a bar in the summer of 2016.