The last of a position-by-position analysis of the Steelers as they are about to report to training camp at Saint Vincent College. Today's installment focuses on the defense:

DEFENSIVE LINE
Even though the entire defense has undergone quite the facelift/youth movement over the past couple of summers, as this camp begins there aren't any open competitions for the 11 starting spots.

This group's starters are Cam Heyward and Cam Thomas at defensive end, with Steve McLendon at nose tackle. And while the development of rookie draft picks Stephon Tuitt and Daniel McCullers might be of more interest to those sitting on the hillsides that ring the practice field, this unit is going to live-or-die with those three veterans.

To those within the organization, Heyward already is seen as a team leader, a linchpin, a significant presence in the locker room. This type of status within a professional sports team only is earned with on-field production, and Heyward works too hard and cares too much not to continue to be productive. Being great is the next step for him.

The defense is going to need McLendon to take the next step in his development. Already having come a long way – from an undrafted rookie from Troy to an NFL starter – McLendon should use these upcoming afternoons vs. Maurkice Pouncey to hone his skills. In the 1990s, Joel Steed used his summers vs. Dermontti Dawson to go from a third-round pick who played little as a rookie into a Pro Bowl nose tackle six years later. McLendon is going into his fifth NFL season.

Coordinator Dick LeBeau has cited the signing of Thomas as one of the significant moves of the offseason, and his versatility could open the door for one or both of the rookies to get onto the field if they show they deserve it. Tuitt is a defensive end, and therefore could benefit from Thomas' ability to play the nose; and McCullers is a nose tackle who could get some snaps based on Thomas as a defensive end.

There figures to be s sixth spot, at least, available to a defensive lineman on the opening 53-man roster, and that competition looks to be wide open. Just as it often happens with offensive linemen, availability for practice every day, which is the key to improvement, can be the difference.

LINEBACKERS
The development of this group is the most significant issue for the Steelers defense in 2014, because the linebackers in a 3-4 scheme are most often the catalyst for big plays. And the Steelers are going to need more big plays – sacks and takeaways – from this defense than they managed in either 2012 or 2013.

The starters right now are Jason Worilds and Jarvis Jones on the outside, with Lawrence Timmons and Shazier on the inside. In truth, the Steelers will be breaking in three new guys at linebacker this season, because even though Worilds will be in his fifth NFL training camp, it'll be his first as a starter on the left side.

Since 2000, the Steelers never have been serious contenders in any season where they didn't get lots of big plays from their linebackers, and so even though camp opens with the starters set it will be interesting to see how the quartet uses August to develop and establish an identity.

The next order of business here is rounding out the depth chart, and right now the possibilities seem quite interesting. Sean Spence has a chance to fulfill the promise he first flashed on these same fields in 2012. What does Chris Carter have to do to make this team? How about Terence Garvin and Vince Williams? Is what they showed last year going to be enough this year? Can Arthur Moats really play all four spots? Where does rookie Jordan Zumwalt fit in?

Similar to the offensive line, it would be nice for the four starters to be able to work as a unit throughout this process, unencumbered by the nagging injuries that can rob them of practice time. There is some real talent here, but it's all new: either new to the NFL, new to the Steelers, new to the starting lineup, or new to this group of linebackers. It would be helpful if this camp turned new into familiar.

SECONDARY
The only difference in the starting group is Mike Mitchell (pictured above) replacing Ryan Clark at free safety, but the overall improvement in team speed on defense can help make this unit better even without wholesale personnel changes. Late in the offseason program, LeBeau said this about being faster: "Well, speed is always a valued entity in defense. The faster you are the more mistakes you can make and catch up to them."

Last year the Steelers defense, particularly the secondary, didn't catch up to too many mistakes, as evidenced by the fact the unit allowed 17 plays of 40-plus yards. Seventeen. The Steelers barely allowed 17 plays of 40-plus yards in the five complete seasons from 2008-12.

To the consternation of their fans, the Steelers didn't get around to addressing their secondary until the fifth round of the 2014 draft when they selected cornerback Shaquille Richardson, by no means a finished product by the way. The personnel has changed very little, and so for the Steelers to change the results they're going to have to do what they can with what they already have.

William Gay, Shamarko Thomas, Will Allen, Antwon Blake, Brice McCain, Robert Golden. These are the experienced players behind the four starters, and Richardson will be in the mix with them in the competition for playing time. With the proliferation of multiple-receiver formations on offense, defenses have to answer with personnel packages to deal with those. That's where the time at camp can be most useful – in determining who is best where.