One of the biggest reasons for the New Orleans Saints' defensive struggles in 2015 is also one of the team’s biggest reasons for optimism going forward: They played a lot of rookies.

According to ESPN Stats and Information, the Saints led the NFL by far with 3,040 defensive snaps played by rookies -- ahead of the No. 2 Chicago Bears (2,483) and No. 3 Cleveland Browns (1,637).

That doesn’t even count the 886 snaps played by first-year cornerback Delvin Breaux, who migrated to New Orleans from the Canadian Football League.

"We had a lot of play by first-year and rookie players, I think the most in the league," Saints general manager Mickey Loomis pointed out last week as he discussed the defense. "That's encouraging on the one hand, because we like the talent. We've got room to grow here with these guys. We have to supplement that with some additional talent."

Most of the Saints' rookie snaps came from linebackers Stephone Anthony (928) and Hau'oli Kikaha (577) and defensive linemen Bobby Richardson (549) and Tyeler Davison (497).

Anthony led all NFL rookies with 112 tackles, starting all 16 games at middle linebacker. The first-round draft pick from Clemson was named to the Pro Football Writers Association’s all-rookie team on Tuesday.

Anthony was also the player ESPN NFL Draft analyst Mel Kiper Jr. was most enthusiastic about when he re-graded New Orleans’ 2015 draft class on Wednesday.

Kiper only bumped the Saints up from a C to a C-plus, because he pointed out that it was hard to tell if the Saints’ rookies would have played as many snaps on more talented defenses.

I agree with Kiper, who referred to the Saints' top pick -- offensive lineman Andrus Peat -- as an "unknown." The jury is still out on most of the Saints’ nine-man rookie class. But the quantity alone offers a great deal of potential.

Four other rookies also played snaps for New Orleans' defense: CB Damian Swann (211), DE Tavaris Barnes (125), DE Obum Gwacham (90) and DT Kaleb Eulls (63).

Only two rookies played snaps on offense -- Peat (406) and running back Marcus Murphy (1).

The Saints ranked 29th in the NFL with just 407 snaps played by rookies on offense.

Overall, they ranked third in the NFL in total snaps played by rookies (3,447 -- behind the Tampa Bay Buccaneers' 4,868, and the Bears’ 3,625).

It was hard to produce a specific number of snaps played by all first-year players (which would include guys like Breaux and receivers Willie Snead and Brandon Coleman). But ESPN Stats and Information put together a list of total snaps played by players in the first 16 games of their career during the 2015 season.

The Saints ranked second on that list with 6,175 snaps and first on defense with 3,926.