Antonio Brown has been ruled out of the Pittsburgh Steelers' game against the Denver Broncos with a concussion.

Sources said Brown told people in the building he was optimistic he could return, but that was hardly a guarantee considering the sensitive nature of concussions. 

Brown has consulted an NFL-approved, offsite neurologist daily.

ESPN's Bob Holtzman reported earlier in the week that things were "not looking good" for Brown, who took a vicious hit from Bengals linebacker Vontaze Burfict in the final minute of the Steelers' 18-16 wild-card win.