Ndamukong Suh Lions 2015
Lions defensive tackle Ndamukong Suh, middle, will be one of the NFL's most coveted free agents this offseason. Reuters

With a limited amount of salary cap space and almost triple the dead money than most any NFL team, Detroit Lions general manager Martin Mayhew must find a way to retain his best defensive tackle Ndamukong Suh, at the cost of some key contributors in the secondary and offensive line when free agency begins next month.

Given the current structure of the Lions’ salary cap, how Mayhew accomplishes such a task could decide whether the Lions make a second straight appearance in the postseason. Detroit has a middling amount of cap space ($15.1 million), even after restructuring both receiver Calvin Johnson and quarterback Matthew Stafford’s massive contracts in 2013.

The Lions also have $13 million in dead money counting against their cap next season, which is usually a tabulation of money spent on cut or traded players, but ironically $9.7 million of that figure is due to restructuring Suh’s deal current deal in previous years.

The Lions have one of the largest pay discrepancies between offense and defense in the league, with $70.3 million devoted to the offense and $37.6 million to defense, according to Spotrac.com. Only the New York Giants, Atlanta Falcons and Buffalo Bills have comparably one-sided payrolls.

Johnson’s seven-year, $113.45 million contract begins its most expensive years next season, raising his cap hit from $13 million last season to $20.5 million in 2015. And in 2016, that jumps to $24 million. Stafford’s cap figure for next season is $17.7 million and moves to $22.5 million in 2016.

The good news is, other than Suh, and fellow defensive tackle Nick Fairley, very few of Detroit’s top free agents figure to command cap-busting deals. And Johnson was quoted earlier this month by the Detroit Free Press saying: “I’ll do whatever I got to do.”

Suh, who led the team with 8.5 sacks last season and has 36.0 total during his five-year career as one of the most fearsome defensive lineman in the league, figures to desire a new deal similar to that of Houston Texans defensive end J.J. Watt’s six-year, $100 million extension.

Despite his behavioral issues on the field and sometimes dirty play, Suh holds most of the bargaining chips. At 27, Suh has barely scratched the prime of his career, making him one of the best young defensive stars in the league and upping his value on the open market.

Secondly, it would be cheaper for the Lions to negotiate a long-term deal with Suh rather than placing the franchise tag on him. The current tag would cost Detroit $26.7 million next season, according to NFL.com, a figure it couldn’t and wouldn’t want to cover for just one year.

Perhaps hoping to gain back some leverage, the Lions will reportedly let Suh gauge his value on the open market next month, but it may be a dangerous plan. For one, if they let Suh walk then Detroit will have to re-sign and rely on Fairley or veteran C.J. Mosley. Fairley missed eight games last season due to injury and its unknown if he can be just as good a pass rusher without Suh by his side.

Mosley will turn 32 before next season, and though he’s unlikely to command a huge deal, he’s not a long-term option for the Lions.

Instead, Mayhew’s plan will likely involve re-signing Suh to a back-loaded deal heavy on guaranteed money that will allow him to tinker with the offensive line. It could add to the Lions’ dead money number, but they opened a big window with an 11-5 finish last season and were arguably one play away from their first playoff victory in more than two decades. The Lions owned the No. 2 total defense in the league last year, and Suh was one of the biggest reasons why.

Meanwhile, the Lions have several decisions to make on the offensive line. Starting right guard Rob Sims has stated that he hopes to be back with the Lions, while center Dominic Raiola's time is Detroit is over. Offensive tackle Corey Hilliard, who played in just one game in 2014, may return in a backup role if the Lions feel he is healthy, while Garrett Reynolds might be retained as a reserve on the right side. Hilliard and Reynolds are both in their late 20s and not expected to seek high-priced deals. Together last season, Hilliard and Reynolds represented a $2.1 million cap hit for an underachieving and injury-riddled line that conceded 45 sacks.

However, if Suh inks a cap-friendly deal and Johnson and Stafford agree to rework their deals again, the Lions could chase one of several notable offensive linemen. There’s the San Francisco 49ers' Mike Iupati, Green Bay Packers' Bryan Bulaga, Tennessee Titans' Michael Oher or Washington Redskins' Tyler Polumbus, but all will command lucrative contracts.

The Lions are likely to save some money by letting outside linebacker Ashlee Palmer and veteran cornerback Rashean Mathis walk next month. Detroit has plenty of depth behind Palmer with third-year linebacker Josh Bynes already in tow, and last year’s second-round pick Kyle Van Noy likely to be healthy after an injury-plagued rookie year.

Mathis, who was third on the team with nine passes defended and one interception, will be 35 when training camp rolls around and the Lions can’t take the risk of signing him to a deal longer than one year. Instead, 27-year-old free agent defensive back Cassius Vaughn is likely to get a new contract and fill Mathis’ considerable role.

Mayhew will also have to keep his eye on the future, with inside linebackers and last season’s top tacklers DeAndre Levy and Tahir Whitehead both hitting free agency in 2016, and No. 1 cornerback Darius Slay up for a new deal in 2017.

Of course, the Lions could plug their holes on the offensive line and the secondary with their No. 23 overall pick in May’s draft, and six more picks in the subsequent rounds.

When Detroit is on the clock late in the first round, cornerbacks like Washington’s Marcus Peters, Miami (Ohio)’s Quinten Rollins or Florida State’s P.J. Williams will probably be available. Offensive tackle Andrus Peat is a potential star, but it's doubtful he will be available at No. 23.

And a number of guards figure to be available in the second round, like A.J. Cann (South Carolina), Laken Tomlinson (Duke) and Tre' Jackson (Florida State). Alabama's Arie Kouandjio is an intriguing possibility due to his talent and injury history.

Finding a replacement for Suh in the draft can’t be ruled out either. USC’s Leonard Williams will likely be a top five selection, but Oklahoma’s Jordan Philips, standing 6-foot-6 and 334 pounds, has much of the size and strength of a Suh. Eddie Goldman (Florida State) and Carl Davis (Iowa) may be available at No. 23, as well.