Hassenauer played three snaps in Saturday's preseason game against the Chiefs.
Reports of Hassenauer's knee injury surfaced two weeks ago, and while he only played three snaps in Saturday's game, he was healthy enough to be made active.
Hassenauer is dealing with a knee injury, Missi Matthews of Steelers.com reports.
The specifics surrounding Hassenauer's knee injury remain unknown, but he'll be considered day-to-day until further notice. He's currently battling for a depth role on Pittsburgh's offensive line.
Hassenauer signed a one-year deal with the Steelers on Friday, according to Jeremy Fowler of ESPN.
Following a stint on the Falcons practice squad, Hassenauer played for the Birmingham Iron of Alliance of American Football. He'll enter camp competing to back up center Patrick Morris as depth out of camp.