Rashean Mathis, Darius Slay lead an otherwise unknown cornerback group

The Detroit Lions open training camp on August 3 and with it, the 2015 season will commence. In a change from most seasons, the Lions are coming off a playoff berth and one of the best seasons in franchise history.

Can the Lions repeat that? Each day from now until training camp, we will look at one position group to prepare for the 2015 season.

Position: Cornerback

Starters: Rashean Mathis, Darius Slay

Backups: Alex Carter, Josh Wilson, Quandre Diggs, Nevin Lawson, Chris Owens, Mohammed Seisay, Crezdon Butler.

Position status: A little up in the air.

Position thoughts: As long as Rashean Mathis plays at close to the level he did in 2014, this group is really strong at the top with Mathis and Slay. Combined, the two were one of the best cornerback tandems in the league last season and if Slay continues his improvement from Year 2 to Year 3, he could come close to being at a Pro Bowl level.

After that, there should be concerns. The Lions really don’t have a third outside corner with any experience right now as that role would fall to third-round pick Alex Carter. In the slot, Detroit has three options -- veteran Josh Wilson, rookie Quandre Diggs and kind-of rookie Nevin Lawson. Each present their own issues. Wilson has now been on three teams in three seasons. Diggs is a rookie. Lawson barely played before a nasty foot injury ended his season in Week 2. One of those three guys will end up as the starting nickel corner but none really have the height or skill set to be a good third outside corner.

Considering two of them are rookies and Lawson was a fourth-round pick last season, it likely means those are the six players Detroit is going to go with to start the season. Owens, Seisay and Butler all have a shot at the roster, but they would have to make major plays in camp.

What the Lions need to see in camp: Ideally, the Lions would see Carter take an abnormal jump as a first-year cornerback that the team could rely on in an injury situation. If that happens, it would be a massive benefit for Detroit and give the Lions confidence both in the present and the future. Carter has the mental makeup to make the transition fast -- Stanford-educated and an NFL pedigree -- but it is often difficult for college corners to make that jump.

The other thing to pay attention to is at nickel. With Lawson essentially sitting out the spring, Wilson and Diggs started the competition in the spring and seem to be going into training camp close to equal. If Diggs were to win the nickel job -- and that is a definite possibility -- the Lions would then have to decide whether it is worth keeping Wilson or going with Diggs and Lawson as the nickels and giving that roster spot to another outside corner, a fifth safety or maybe even a linebacker, receiver or running back depending on special-teams needs.

If Wilson wins the job, expect Detroit to keep six corners unless Lawson isn’t able to come back from the injury.

Who ends up on the roster: Mathis, Slay, Carter, Wilson, Diggs, Lawson.