Johnson didn't practice Wednesday due to a knee injury, Teresa Varley of the Steelers' official site reports.
Johnson wasn't included Tuesday on the team's initial Week 15 injury report, so his absence from Wednesday's practice is notable. What the wideout is able to do Thursday -- if anything -- thus looms large in terms of his chances of facing the Colts on Saturday. If Johnson is sidelined this weekend, Calvin Austin and Miles Boykin would be candidates to see more reps alongside starting wideouts George Pickens and Allen Robinson.