It was easy to see some of the ways the Saints' offense changed last season.

Everyone noticed it. Teams started to stack the box because they thought they had a better chance of winning when Drew Brees was passing the ball than when it was in the hands of Mark Ingram and Alvin Kamara.

But other changes were also happening. The way Brees distributed the ball, and the routes often targeted, changed from previous seasons. The numbers also illustrate a potential area of need for the Saints.

On a macro level, the distribution charts are pretty similar, outside of one key difference. Brees went from throwing 58 screen passes in 2015, to 49 in 2016, to 85 in 2017. You have to pull back some layers to see the difference, and a lot of it can be traced to how New Orleans approached the slot.

The first thing to understand is how the cast changed. Brandon Coleman led the Saints with 237 routes from the slot, according to Pro Football Focus, but Ted Ginn Jr. (128 routes) and Michael Thomas (116) also saw a good amount of work from the inside. Thomas led the Saints with 36 catches for 421 yards from the position.

Previously, Willie Snead was the undisputed leader from the slot, logging 707 yards from the position in 2016. But after he disappeared from the offense, the approach changed. It was a must. Snead and Thomas are different players who excel in varying ways.

Now, keep in mind Brees threw 673 passes (45 percent to receivers lined up inside) in 2016 compared to 536 (41 percent) last season. The raw figures must be viewed through that prism. So, the fact that the Saints targeted 15 slant routes from the slot last season as opposed to 14 in 2016 shows a significant change.

But there are more staggering differences. For instance, Brees only targeted nine dig routes (an in-breaking route down the field) from the slot last season. That number sat at 32 in 2016, according to Sports Info Solutions. Snead and Brandin Cooks, who was traded to New England before last season, accounted for 22 of those targets in 2016.

And then there's the drag (crossing) route. Brees targeted it 21 times from the slot in 2017. The number sat at 38 in 2016. Again, this was an area where Snead excelled, being targeted 14 times on the pattern in 2016. Thomas, however, also turned it into a weapon by catching eight passes on it last season for 85 yards out of the slot.

The out route shows another big difference. The number sat at 55 in 2016 and 35 last season. Once again, Snead (18 targets) and Cooks (19 targets) led the way two years ago. Last year, Thomas caught 13 outs from the inside, but there was no one else to help him carry the remaining load.

The changes raise an interesting question for the offseason. There's no reason that Snead can't bounce back and reassert himself as a key component of the offense after performing at a high level his first two years with the team. However, if for some reason he is no longer part of the plans or can't be trusted to reclaim his role, do the Saints need to find a full-time player to man the slot?

A lot of the issues New Orleans endured in the passing game can be traced back to not having that trusted receiver working from the inside. Snead was a safety valve, if not a first option, on third downs. That player didn't exist last season unless it was Thomas moving inside.

There are advantages to Thomas being able to move inside. It can create problems for the defense, and at times get him off of a cornerback who is shadowing him. But if he's going to take on more of a role there, then someone else needs to be brought in to fill his spot on the outside.

It seems unlikely that will be the approach. New Orleans likes Thomas on the outside. The slot should only be a wrinkle for him. In that case, the team could use someone who can do the things Snead used to do from that spot on the field. Otherwise, the offense could continue to suffer.

Now, there might be more than one way to go about this. A receiving tight end could help alleviate the burden. Kamara could also help to cover up some of the issues in a more expanded role. But one way or another, this team needs to add an offensive weapon.

Maybe the answer is getting Snead back on track. If it is not, then New Orleans needs to find an answer.

Follow Nick Underhill on Twitter, @nick_underhill.​