Cornerback could be secondary concern for Lions

This is the seventh in a series looking at positional needs for the Lions in free agency.

Allen Park — As surprising as it sounds, the Detroit Lions’ secondary is among the team’s most stable units.

Cornerback Darius Slay is a standout, and after signing an extension last offseason, he’s locked up for the foreseeable future. Upgrading Nevin Lawson, on the opposite side, is certainly a possibility, but far from Detroit’s most pressing need.

At safety, Glover Quin is a rock, but is quietly entering the final year of his contract. Extending him is always an option, but at 31 years old, the Lions would be wise to consider a long-term solution at the spot, perhaps through the draft.

Tavon Wilson, a free-agent addition last season, did a fine job plugging the vacant strong safety spot. He also has one year left on his contract, while Miles Killebrew made a positive impression as a rookie and looks to be the team’s future at the position.

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Nickelback is probably the biggest area of concern. Quandre Diggs is a fierce competitor, but simply wasn’t good enough in coverage last season. And when he went down with a season-ending injury in December, the back end struggled even more.

The Lions can upgrade at cornerback a number of different ways. They could look for a potential replacement for either Lawson or Diggs, or they could double-down on the young pair, counting on continued development, while bolstering the depth behind them.

The market looks like it will be flooded with high-quality options at the top, led by Trumaine Johnson and A.J. Bouye.

Johnson, who played under the franchise tag last season, is your traditional big corner, standing at 6-foot-2 and weighing more than 200 pounds. He is a physical presence on the outside and would fare well in the Lions scheme, which will concede some short throws in exchange for quick tackles and minimal gains after the catch.

Bouye emerged last season as one of the league’s premier ball hawks. With experience inside and outside, few have the anticipatory skills of the six-footer who broke up 16 passes in 2016 while allowing just 47.5 percent of the passes thrown his direction to be completed. That’s a big improvement from Lawson’s 63.2 percent.

Another intriguing option at the top of the market is New England’s Logan Ryan, given the obvious ties to Detroit general manager Bob Quinn. Ryan also offers inside-outside versatility with 13 interceptions and 41 passes defended in his first four seasons.

If the Lions are interested in more of a short-term option, someone who could push Diggs for his starting job, Darius Butler fits the bill. He’ll be 31 by the time the season starts, but still showed plenty of skill in coverage with the Colts last season, intercepting three passes and breaking up seven in 12 games.

■Lions DBs under contract: Darius Slay, Nevin Lawson, Quandre Diggs, Johnson Bademosi, Rolan Milligan, Glover Quin, Tavon Wilson, Miles Killebrew, Don Carey, Charles Washington

■Lions free agents: Rafael Bush, Asa Jackson, Crezdon Butler, Alex Carter (ERFA), Adairius Barnes (ERFA)

■Top free agents: A.J. Bouye, Trumaine Johnson, Stephon Gilmore, Logan Ryan, Morris Claiborne, Eric Berry, Tony Jefferson, Johnathan Cyprien, Barry Church, Bradley McDougald