The Beaver County Times reported Tuesday that continued swelling in the knee could lead to arthroscopic surgery for the All-Pro linebacker.
Harrison's agent, Bill Parise, hinted that a procedure could be coming soon, so that the team could remove him from the physically unable to perform list before the season begins. If Harrison were to begin the season on the PUP list, he'd be forced to stay on it for six weeks.
"If it doesn't respond the way everybody wants it, that sounds like the alternative," Parise said of the scope. "We'd probably opt for that sooner than later."
Parise downplayed the situation, saying Harrison "is probably healthier now that he's been in three years." But the Steelers can't help but be concerned about a lingering knee issue for their 34-year-old star.
Follow Dan Hanzus on Twitter @danhanzus.