Harrison -- dealing with irritation in his surgically repaired left knee -- has yet to practice this week. He worked out Monday and was scheduled to be evaluated after a running session on Wednesday.
"We will work him up to activity and see how his knee responds," Tomlin said, via the Pittsburgh Tribune-Review.
In other injury news, Rashard Mendenhall (knee) practiced in full on Wednesday. Mendenhall's Week 2 status is undetermined, but expect to see a backfield-by-committee against the Jets regardless. Jonathan Dwyer (43 yards on nine carries) did some good things against the Denver Broncos, earning rope from his coach in the process.
Said Tomlin: "(Dwyer) provided a spark play, represented himself well and will probably get an increased opportunity."
Due to the nature of their injuries, Harrison and Mendenhall are both wild cards for the Steelers. The timetables are fluid, their effectiveness unknown.
Follow Dan Hanzus on Twitter @danhanzus.