The Steelers need to bolster their defense, however the D-Line may be the strongest unit on that side of the ball with Cam Heyward, Stephon Tuitt, Javon Hargrave, Tyron Alualu and L.T. Walton up front. While I don't think there will be much addressed here, you never can tell. Here are the top options for teams looking for help up front.
Muhammad Wilkerson - New York Jets
The veteran has 44.5 career sacks and can still get to the passer. He was paid 87 million over five years after the 2015 season, but his play declined a bit. Wilkerson still has the potential to be really good and rebound. Probably not in Pittsburgh though.
Sheldon Richardson - Seattle Seahawks
The former Jet, a Pro Bowler in 2014, was traded to Seattle in mid season last year and finished with only one sack last year. But Richardson is versatile. He plays both the 3-4 and 4-3, while rushing the passer and stopping the run ably. He should be out of the Steeler price range.
Ezekiel Ansah - Detroit Lions
Ziggy had 14.5 sacks in a dominant 2015 campaign, but hasn't approached that number since because of injuries. The Lions franchised Ansah, so he won't be going anywhere.
Trent Murphy - Washington Redskins
The Redskin is a solid rusher off of the edge, but missed all of 2017 with an ACL/MCL tear. Murphy had 9.5 sacks in 2016 and is expected to return in 2018.
Other Notable Free Agent Defensive Linemen:
Kony Ealy - New York Jets
Dontari Poe - Atlanta Falcons
Justin Ellis - Oakland Raiders
Alex Okafor - New Orleans Saints
Adrian Clayborn - Atlanta Falcons
Bennie Logan - Kansas City Chiefs
David Irving (RFA) - Dallas Cowboys