CINCINNATI -- Linebacker James Harrison was among a trio of Cincinnati Bengals who missed Thursday’s practice with an illness that appears to be spreading around the team.

Running back BenJarvus Green-Ellis was the first to miss a workout this week because of the bug. He was out Wednesday. Green-Ellis also was out for part of Thursday. Even though he took part in a walkthrough early Thursday morning, he went home before the Bengals went through their full practice later in the day inside the University of Cincinnati’s practice bubble. Also missing from that practice was Harrison and fellow linebacker Vontaze Burfict.

The AFC North-leading Bengals (9-4) expect the trio to play Sunday in Pittsburgh against the Steelers (5-8) but are trying to be careful because of the illness.

Harrison apparently was so ill he didn’t come to Paul Brown Stadium at all Thursday. He had been expected to speak with reporters during the afternoon about his return to Pittsburgh. This season is the first the 12-year veteran has played for a team other than the Steelers. He signed with Cincinnati during the offseason after failing to come to terms on a restructured deal with Pittsburgh.

Sunday’s game will be Harrison’s first inside Heinz Field since his departure.

He enters the homecoming game with 27 tackles, two sacks and an interception.

Here is the full Bengals' injury report:

Did Not Participate in Practice

LB Vontaze Burfict (illness/thigh)

LB James Harrison (illness)

RB BenJarvus Green-Ellis (illness)

CB Terence Newman (knee)

Limited Practice Participation

DE Wallace Gilberry (knee)

WR Marvin Jones (shoulder)

Full Practice Participation

S George Iloka (concussion)

OG Kevin Zeitler (foot)