NEWCASTLE UPON TYNE, ENGLAND – SEPTEMBER 26: Jose Mourinho, Manager of Chelsea during the Barclays Premier League match between Newcastle United and Chelsea at St James’ Park on September 26, 2015 in Newcastle upon Tyne, United Kingdom. (Photo by Tony Marshall/Getty Images)

What has happened to Chelsea this season?

While Chelsea may have avoided their worst start to a Premier League campaign in the club’s history this past weekend, it showed that there is still a lot to improve upon at Stamford Bridge after the club’s 2-2 draw with lowly Newcastle this past weekend. Just one year ago, it looked like Chelsea was going to run away with the 2015 Premier League title. Many people had even called the race over by November. A year later, Chelsea are sitting 15th in the table, just four points out of the relegation zone.

How did this happen to a team that’s been a Premier League powerhouse over the past decade and how surprising is it? Most people’s answer to the second question would be “yes I’m shocked,” but there are some, this writer included, who weren’t buying into the Chelsea hype machine.

There’s no denying Jose Mourinho is a great manager. He’s certainly arrogant, but deservedly so. However before the season I felt that Mourinho’s arrogance would be Chelsea’s undoing this season.

This past summer, the storylines were all about how Chelsea’s rivals Manchester City and Manchester United were reloading attempting to reload in the transfer market, while Chelsea was staying put. The club’s only move was losing an old injury prone striker who could still score goals (Didier Drogba) and replacing him with an old injury prone striker who can’t score goals anymore (Radamel Falcao).

Chelsea’s undoing so far this season has been the depth of their squad, or rather the lack there of. This is partially Mourinho’s fault but more of the blame falls onto owner Roman Abromovich’s outrageous demands of winning everything and not having any patience.

Similar to Manchester United’s great teams of the ’00’s, Chelsea’s team was built around the backbone of a very strong core. Players came and go, but down the middle of the field there was always Petr Cech, John Terry, Frank Lampard and for the most part Ashley Cole and Didier Drogba. As Manchester United learned in 2014, you can lose a few of those pieces over the years, but once you’re down to just one, you better have their replacements ready or otherwise you’ll fall quickly.

Herein lies the problem for Chelsea. Due to the win-now-or-I’ll-be-sacked pressure that Chelsea managers face, it has meant that over the years they played the same team every match. There was never a chance to slowly start rotating some of their younger players into the team and get them acclimated to the first team.

This is now starting to catch up with Chelsea. The spine that Chelsea came up with has either moved on or gotten old. On their back line, John Terry and Barnislav Ivanovich have both gotten very old very quickly. There’s no predicting when a player will lose their form due to age, some do it much quicker then others but it is something you have to be mindful of when dealing with two players in their 30’s.

Don’t forget to factor in that Mourinho typically likes to work with a small squad. Working with a small squad does have it’s benefits such as there are less players that you have to leave out of the squad each match, and that’s about it. Chelsea operates with a squad nearly the size of Everton’s, which is ridiculous when you remember the different amounts of money those two clubs have.

The small squad is problematic for two reasons. The first and obvious one is when you have players not performing, you don’t have anyone to replace them with. The second is the problem Chelsea are currently dealing with. They have to play almost the same starting XI every match, which leads to players getting tired.

Last season Chelsea started out on fire but eventually the amount of matches started to catch up to them. Their central midfield pair of Nemanja Matic and Cesc Fabregas looked exhausted by March as Chelsea crashed out of the Champions League and sputtered towards the finish line. They won the league for two reasons: they had built a big lead and because Manchester City couldn’t win down the stretch either.

Playing every week has taken its toll on the players. Fabregas and Matic still look like they haven’t recovered. John Terry has been dropped from the team and Ivanovic could be next.

Then there’s the man the team is built around, striker Diego Costa. Costa has always had injury problems and was a high risk/high reward player when Chelsea signed him. You knew he would score goals, but his hamstrings could also go at any second. It’s a near miracle he stayed fit the entire season last year but this season he too has been ineffective. Somehow this past summer, Mourinho managed to overlook all of this.

At the end of the day, this Chelsea team has so many big names that it’s easy to say “they have the talent and they’ll turn it around eventually.” It’s certainly easy to think that way and believe that. The question is, if these players are already tired, will they really be able to find their form and make it through another long campaign without any rest? Only time will tell.

About Pauly Kwestel

Pauly is a Producer for WFAN in New York and the CBS Sports Radio Network. He has been writing about the beautiful game since 2010 and can be followed on twitter @pkwestelWFAN