If you ask Ottawa Senators fans what they think the teams biggest weakness is, the majority of them will say the blueline. Their defense hasn't been a strongpoint for a long time, and this coming season probably won't be any different. However, they could see some improvement from one specific player which would help the team immensely.
That player is Cody Ceci. If he can become the player that the team and fans expected him to be when he was drafted 16th overall in 2012, then all of a sudden Ottawa is in good shape for defensemen. At the same time, if he stagnates or even regresses, then the situation is a complete 180. The difference between having two solid pairings and one and a half is huge, and the Senators won't be able to take that "next step" that I've alluded to with just three good defensemen.
Don't get me wrong, Ceci hasn't been bad per se so far in his career. You can't really expect much from him in his first one and a half seasons after being a tad rushed to the NHL. He's also only 21, so he has time left to develop. But I certainly would not define him as a quality top-four defenseman just yet, as his underlying numbers aren't so strong. He has also relied heavily on Patrick Wiercioch so far, and he needs to show that he can succeed on his own.
During Ottawa's amazing run last year, the second pairing was almost always Wiercioch and Ceci, so they got quite familiar with one another. Here is what they looked like together and away from each other at 5 on 5:
As you can see, they were fantastic together, and everyone can agree with that. 13 goals for and 10 against is very solid, and a CF% of 53.3% is also a very good sign. 402:04 together isn't a large enough sample to say that kind of performance will stay the same, but it's a decent amount of evidence. The problem is, when Ceci wasn't playing with Wiercioch, his CF% dropped to 46.8%, and his GF% was even worse at 43.9%.
Wiercioch on the other hand didn't struggle without Ceci, putting up an even GF% at 50% and a better corsi at 55.4%. It's pretty clear that at least year Ceci was the weaker link in the equation, and he needs to play better on his own.
Furthermore, his HERO chart is only partially encouraging:
He's known to be an offensive player, so it's good to see that he at least is producing points at a good rate over the past one and a half seasons. He still only has 30 points in 130 career games though, so it would be nice if he could get perhaps 30+ points this season to give Ottawa another offensive threat. His possession numbers show him as more of a bottom pairing player though, which is in stark contrast to Wiercioch.
As of now, Ottawa has a clear hierarchy of their three best defensemen in Erik Karlsson, Marc Methot, and Wiercioch. After that, most people assume Ceci will be the number four, but I don't think he's there yet. Mark Borowiecki won't be anything more than an average bottom pairing player/7th defensman, Jared Cowen is one bad stretch of games away from having no value left, Chris Phillips may have played his last game, and Chris Wideman hasn't played an NHL game.
While I do like Wideman's upside, we don't know how his game will translate to the NHL. Ceci looks to be the only option to play on the second pairing right now, and a lot of the team's success hinges on him developing. If he succeeds, then there will be four quality players on the blueline for now, and next year they can add even more with someone like Mikael Wikstrand, or Fredrik Claesson. But if he fails, then there is a strong chance that Ottawa won't make the playoffs.
Good teams typically don't win with just three good defensemen, and there would be too much pressure on Wiercioch to compensate for him. Ottawa can most likely get by if Ceci gets dragged along by Wiercioch again, but the team would improve dramatically if he becomes his own player.
I said a while ago that Anderson is the most important piece for Ottawa this year because of how much his game could sway one way or the other, but Ceci has an almost equally important role. If the Senators improve again this year, you can bet Ceci is a big reason why.