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Another in a position-by-position series examining the Steelers roster in advance of the start of free agency on March 10:*

DEFENSIVE LINE
(Free Agent Scorecard: 1 unrestricted – Clifton Geathers)

MATT CONRATH
This 6-foot-7, 290-pound defensive end was signed by St. Louis as an undrafted free agent from Virginia in 2012, and he bounced between the Rams roster and practice squad for a couple of seasons until being released in 2014. He signed a futures contract with the Steelers on Jan. 9.

CLIFTON GEATHERS
Geathers was signed off the street on Dec. 1 after Brett Keisel sustained a torn triceps that needed surgery and landed him on injured reserve. Geathers didn't play a snap, and in fact he was inactive for every game he was on the roster. His size – 6-foot-8, 325 pounds – looks intriguing on paper, but there is nothing really to go on except some practice reps at a time during an NFL season where wearing pads is largely prohibited by the Collective Bargaining Agreement.

ETHAN HEMER
Hemer was brought back onto the practice squad when the Cardinals plucked Josh Mauro off and onto their 53-man roster on Nov. 14. He will get a chance to participate in the offseason program, with the culmination being a second trip to Latrobe. That will be the critical time for him.

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CAM HEYWARD**
In so many ways, Cam Hayward and Maurkice Pouncey are mirror images of each other. Both are superior athletically to the rest of those at their position. Both want badly enough to be great to do all the little, pain-in-the-butt things that go into making that happen. Both are leaders. Alphas in the locker room. Unselfish. They are a couple of the key vertebra in this new backbone these Steelers are growing after going through so much roster turnover. Since 1992 when this version of the Steelers 3-4 was born, only twice have defensive linemen led the team in sacks – Kimo von Oelhoffen with eight in 2003, and Aaron Smith with eight in 2004. Heyward tied Jason Worilds for the lead this past season with 7.5. A true difference-maker.

BRETT KEISEL
One calendar year ago, the Steelers were in a similar position. They knew they were going to have to get younger on defense, that the time for cutting ties with some significant components from their recent past was at hand. From their defensive line, Aaron Smith and Casey Hampton already were gone, and it seemed as though Keisel was going to be next. The team signed a veteran free agent and then used a No. 2 pick on a couple of defensive ends while Keisel was without a contract. Then on Aug. 20, the Steelers decided they needed Keisel, and his 13th NFL season was a very productive one until he tore a triceps on Nov. 30 vs. New Orleans. That's a serious injury requiring a long rehab, and Keisel will be 37 in September.

JOE KRUGER
He was added to the practice squad when Kansas City signed Nick Williams off the practice squad to add him to their roster on Nov. 24. A seventh-round pick of the Eagles in 2013, Kruger, 6-foot-6, 290, also has spent time on the practice squads in San Diego and Green Bay. His brother is Paul Kruger, formerly of the Baltimore Ravens and now an outside linebacker with the Cleveland Browns.

DANIEL McCULLERS
He showed enough to indicate why the Steelers believed McCullers was a nice developmental prospect as a nose tackle, and he also showed enough to see why he didn't get more playing time as a rookie. McCullers (6-foot-7, 352 pounds) has some work to do this offseason, but he is an example of The Planet Theory, which unequivocally states that there are only so many men on the planet who are that big and have athletic ability. McCullers will celebrate his 23rd birthday at training camp this summer.

STEVE McLENDON
The Steelers finished sixth in the NFL in 2014 in rushing defense, and it was clearly better when McLendon was on the field. He started 11 games and played in 12 last season despite a shoulder injury that was both painful and a real detriment to doing the things required of an NFL nose tackle. When teamed with Cam Heyward and Stephon Tuitt, McLendon gave the Steelers a group with the mobility and athleticism to counteract the outside-zone schemes that rely on chopping down the defensive linemen. A McLendon-McCullers 1-2 punch at nose tackle in 2015 could be just what the run defense needs.

CAM THOMAS
He was below the line early in the season, but then got better. But overall, Thomas' first season with the Steelers upon arriving on a wave of optimism as a signing during the first week of free agency last March has to be considered a disappointment. He finished with 19 tackles, one-half sack, and six pressures, but numbers aside there just never seemed to be any bang for the free agent buck. Time will tell if he's to get another chance, or maybe the Steelers go shopping again for what they hoped they were getting in Thomas.

STEPHON TUITT
His playing time increased significantly after Brett Keisel went on the injured reserve list on Dec. 1, and Tuitt quickly showed he belonged. Athletic and energetic, Tuitt can make plays all over the field, and he showed a knack for hustling to the football and laying big hits on guys not expecting a defensive lineman down the field. (Jamaal Charles can testify to that.) The starting job should be his for the foreseeable future, and the extra good news is that Tuitt won't turn 22 until mid-May.