Ebron injured a knee last week against the Los Angeles Chargers, apparently during his fourth-quarter touchdown. He is expected to miss extended time with surgery, a source told ESPN's Jeremy Fowler earlier this week.
Ebron was a co-starter along with rookie tight end Pat Freiermuth. He has had a reduced role this season with just 12 catches for 84 yards and a receiving touchdown as well as a rushing TD.
Hassenauer, who was starting in place of guard Kevin Dotson, injured a pectoral muscle early in the loss to the Chargers. Tackle Joe Haeg replaced Hassenauer a week ago, but the Steelers are likely to turn to B.J. Finney, a veteran interior offensive lineman, to replace him in the long term.
With both Dotson and Hassenauer now on IR, the Steelers signed practice squad offensive lineman John Leglue to the active roster.