The All-Pro linebacker was limited in practice Wednesday and did not participate in Thursday's session after undergoing knee surgery last month, according to Ed Bouchette of the Pittsburgh Post-Gazette.
Harrison on Thursday posted a pair of signs near his locker. "I will answer all questions on Fridays," read the first. "And only Fridays," read the second, according to Chris Adamski of CBSSports.com.
Harrison told Adamski the hush-hush policy will remain in effect all season. He said he picked Friday because it tends to be a thinner media haul than earlier in the week.
Before missing five games last year, Harrison was a rock, starting 63 games over four seasons for Pittsburgh and emerging as a dominant force from the linebacker position. It's hard to imagine the Steelers' defense without him, but Harrison's chances for playing against the Broncos look less promising by the day.
We'll wait to hear him speak on Friday.
UPDATE: Harrison did speak Thursday -- but only on Twitter. "I will be practicing tomorrow and (will) have a better (idea) if I'll be ready to go on Sunday night," he tweeted.
Follow Marc Sessler on Twitter @MarcSesslerNFL.