It would appear that you can actually being to say that it's truly the twilight of his career. Normally you say that but you know he's still going to get significant playing time. He's still going to get his catches, yards, and touchdowns.
Today though, he was healthy. No ill affects from the concussion like symptoms according to Tomlin after the game. It's just a situation where guys like Brown, Wallace, Cotchery, and Heath Miller are making more plays and their youth is starting to outgain the experience and savvy playing of Hines.
Make no mistake, Ward will still make some catches this year and he'll be a factor in the Steelers record at some point but this receiving corp for Ben is starting to distance themselves from the veteran.