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DEFENSIVE LINE – 7**
(Free Agent Scorecard: 1 unrestricted – Ricardo Mathews)
JAVON HARGRAVE
It's rare for rookie defensive linemen to start for the Steelers, and Hargrave not only started 13 regular season games, but he was a factor. The No. 3 pick from South Carolina State had at least one tackle in 14 of the 15 regular season games in which he appeared – he was inactive on Dec. 11 at Buffalo with a concussion. The only time Hargrave was shut out was in the opener against the Redskins on Sept. 12. Hargrave finished with 27 tackles and two sacks during the regular season, and he had another eight tackles and a sack of Tom Brady in the playoffs. Hargrave is the starting nose tackle and a big part of the Steelers' immediate future on defense.
CAM HEYWARD
When the 2016 season began, there could be little argument that Heyward was the Steelers' best defensive player, and his value to the unit sure seemed to be on the same level as Ben Roethlisberger's value to the offense. In an eight-point win over Cincinnati in Week 2, Heyward batted down two passes and recovered a fumble. Two weeks later in a rout of Kansas City, Heyward had three sacks and batted down two more passes. Trying to play through a hamstring injury, Heyward was inactive for two games with that, and then he landed on injured reserve after tearing a pectoral muscle. That the defense continued to develop after losing Heyward is a tribute to the other players, but it shouldn't be seen as evidence Heyward isn't that important. Because he is. In every era of their NFL existence, the Steelers have been represented by certain individuals whose contributions on the field and professionalism off the field contribute to carry on the legacy of the franchise and its founding family. Cam Heyward is one of those guys for this era. He's signed through the 2020 season.
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Check out the best photos from the 2016 season.
RICARDO MATHEWS**
In back-to-back offseasons, the Steelers signed an unrestricted free agent defensive lineman from the Chargers, and there's no doubt Mathews was the better of the two. Mathews played in all 16 regular season games despite a nagging ankle injury, and Coach Mike Tomlin acknowledged that contribution at one of his weekly news conferences. Fourteen tackles and a sack might not sound like much production, but Mathews stepped up after Heyward went on injured reserve and gave the team professional play on the defensive line. After one season with the Steelers and a potential free agent come March 9, Mathews has a decision to make. Does he want to start over with another team in 2017?
JOHNNY MAXEY
A very nice find for the Steelers as an undrafted rookie from Division II Mars Hill University, Maxey came to training camp, then latched on with the practice squad, then was signed to the active roster for the Christmas Day game against the Ravens. Maxey is raw, but he improved and didn't look out of place whenever he was rotated onto the field. This will be a crucial offseason for Maxey, who's going to have to get stronger as he continues to try to transition from Division II in college to the NFL. He's listed as 6-foot-5, 283 pounds, and he has a chance at an NFL career if he uses 2016 as a jumping-off point.
DANIEL MCCULLERS
There comes a tipping point for every player trying to fashion a career in the NFL. Teams always are looking for younger and cheaper, and so those who don't show something before the next guy comes along, well, they usually find themselves trying to catch on with another team. McCullers is at that point, if it already hasn't passed him by. He's 6-7 and 352 pounds, but McCullers never has shown he knows how to use that size to his advantage, and to the naked eye it doesn't look as though he has improved much over his three seasons with the team. He should assume this is a do-or-die situation.
STEPHON TUITT
When Heyward injured his pectoral and had to go on injured reserve, Tuitt took his game to the next level. Tackles, sacks, his presence on defense, all of it ramped up to a level previously unseen from a former second-round pick who was in his third NFL season. So far in his career, what has become Tuitt's signature play is one where he chases from his defensive line position and lays the wood on the guy with the football at a location on the field where defensive linemen usually aren't laying the wood on the guy with the ball. Tuitt's play is an indication he can be a dynamic defensive player – two forced fumbles on Oct. 2 against the Chiefs, two sacks in Cleveland on Nov. 20 – but what has to come next is Tuitt taking what he did post-Heyward's-injury and contributing at that level over the course of a whole season. That's one of the things this defense is going to need for the Steelers to contend for a championship in 2017.
L.T. WALTON
A former sixth-round pick from Central Michigan, Walton used his second NFL season to hint he could develop into a contributing cog within the defensive line. He's 6-5, 305, will be 25 in late March, and Walton has spent two seasons learning the defense and the game at the NFL level. This offseason Walton has a chance to pass McCullers, and if can stay healthy through camp and the preseason to get the work he's going to need to continue to improve, he has a chance.