Still, Pittsburgh Steelers coach Mike Tomlin thinks the two veteran defenders are hardly the cure-all for a defense that lacked a certain bite during Sunday's season-opening loss at Denver.
Yes, it'll be great to have Clark—who sat out the opener due to a sickle cell trait that flares up at high altitude—back for the home opener against the Jets. And Harrison's aching left knee was good enough to work out on Monday, leaving open the possibility the four-time Pro Bowler could suit up for the first time since January.
Good news to be sure. Just not a cure-all.
"Obviously, those guys are capable of helping us," Tomlin said. "They're quality veteran players. They know how to play and, specifically in Ryan's case, not only his play but his communication and leadership. That remains to be seen and we're not going to assume anything. What we are going to do is focus on the healthy guys and get them prepared to play and, ultimately, expect them to play on the acceptable level."
Something Tomlin thinks didn't happen enough against the Broncos, as Pittsburgh's defense—ranked No. 1 in yards against a year ago—struggled once Peyton Manning and the Broncos went to a no-huddle offense.
Tomlin, however, doesn't think the no-huddle "taxed" the Steelers so much as what happened when the ball was in play.
"The reality is that we didn't play well enough post-snap," Tomlin said. "Forget about whether or not they huddle between plays, we've got full control over how we play once the ball is snapped and it wasn't up to snuff in many instances."
Denver didn't dominate on the ground—averaging just 3.5 yards per carry—but ran it effectively enough with Willis McGahee to keep Pittsburgh off balance. The Steelers sacked Manning twice in the first half and created an early turnover, but did little after halftime. The Broncos scored on their first three second-half possessions, and their fourth was a couple of kneel downs by Manning to end it.
There were bright spots defensively, particularly inside linebacker Larry Foote. The 11-year veteran moved into a starting role after the Steelers released James Farrior in the offseason and Foote responded with eight tackles, including a sack. Linebackers Chris Carter and Jason Worilds played capably while filling in for Harrison, with Worilds providing a sack of his own after missing the entire preseason while recovering from wrist surgery.
Neither Carter nor Worilds, however, are Harrison. Few linebackers in the league are. The 34-year-old has grown frustrated, however, by lingering knee issues and has grown so tiresome of the subject he's promised only to address it one day a week during the season.
Harrison called himself a "game-time decision" before the Broncos, but could only watch from the sideline in a yellow T-shirt and black shorts as the Steelers lost in Denver for the second time in nine months.
The Steelers could certainly use him on Sunday against the Jets (1-0). New York exploded for 48 points while whipping Buffalo in its opener even with new acquisition Tim Tebow playing in a limited role. Tebow lit up Pittsburgh while beating the Steelers in the playoffs last winter as quarterback for the Broncos. He's firmly behind starter Mark Sanchez in New York, though Tomlin warned the Jets just showed "the tip of the iceberg" when it comes to their plans for the versatile Tebow this season.
While Harrison remains questionable, Pittsburgh expects right guard Ramon Foster and right tackle Marcus Gilbert to start against New York. Foster left the Denver game with what Tomlin termed an "optical migraine" while Gilbert hyperextended his left knee.
With the starting right side of the line sidelined, the Steelers had trouble running effectively behind replacements Doug Legursky and rookie Mike Adams, who also had serious issues in pass protection while giving up a late sack.
Pittsburgh hasn't started a season 0-2 since 2002, though that didn't stop the Steelers from finishing 10-5-1 and making it to the divisional round of the playoffs. The Steelers haven't even lost consecutive games since a five-game slide in 2009. They pride themselves on their resilience, but will need it against New York.
"This week is very important," running back Jonathan Dwyer said. "Every week is important. The first didn't go as we wanted, but we are going to make sure we put ourselves in a better situation this week than we did last week."
Follow Will Graves at http://www.twitter.com/WillGravesAP