Chelsea have looked haphazard and directionless in their last two games without their "Captain, Leader, Legend."
With John Terry set to return from injury and also with an eye on a Chelsea contract which expires at the end of this season, what are the key attributes he brings to this Chelsea side that are in such short supply when he's not there?
More than 15 years since his Chelsea debut (against Aston Villa in an October 1998 League Cup tie), Terry is still the best defender at the club.
After a year spent mostly on the sidelines, the Blues captain has returned this season looking almost as good as ever.
Jose Mourinho is a huge part of that, having reunited with the man he made one of the world's best defenders.
He knows, as do most who watch Chelsea, that Terry also has a knack of making whoever he plays alongside a better player—be it Gary Cahill, David Luiz, or going back to Ricardo Carvalho and William Gallas.
Even Petr Cech looks more comfortable with Terry in front of him.
The longevity of John Terry's career at the highest level is nothing short of incredible.
Only three men have played more games for Chelsea (Ron Harris, Peter Bonetti and Frank Lampard) and in those 600+ games, Terry has practically done it all.
There are very few situations into which you can plunge him where he looks uncomfortable.
He has played in front of some of football's most hostile crowds, and he has tended to be the focus of much of their ire. Where others might panic, he thrives on it.
His in-game experience is also legendary.
His understanding of the ebb and flow of a match, of when to go on the offensive and when to shut-out, is bettered by few in the Premier League.
All of that has been accumulated over the nearly 400 Premier League games he has played for Chelsea.
In his absence, and with Frank Lampard and Ashley Cole also largely warming the bench, Chelsea can only call on one outfield player with 200+ Premier League games under his belt: Gary Cahill.
Headstrong, passionate and committed—Terry leads a side as he expects others to follow.
He chases every ball, calls for every throw and pushes himself and his team-mates to the limit.
That commitment sees him get battered and bruised practically every game—very nearly each time picking himself up to play-on.
It is a special sort of never say die attitude that is incredibly rare in football in general and certainly within the Chelsea squad.
Players such as Eden Hazard, Oscar and Samuel Eto'o all bring character of their own to this team. But none of them is able to carry and thrive upon the expectations and emotions of a stadium like Terry does.
Beyond the basics of Terry's character lies a sly understanding of the game that makes him the greatest captain in English and perhaps even world football.
Watching the things he does on-pitch, away from the ball, is a revelation.
Nobody in the Premier League knows how to play a referee better. Making clever decisions about the right battles to fight and communicating with officials in a masterful way.
Without him the armband falls to Frank Lampard (when selected), who is a completely different animal. Much quieter, he captains in a way similar to Steven Gerard at Liverpool: exuding seniority and direction, without being the most vocal of men.
More frequently of late, Petr Cech has had the responsibility. He has shown several times that he has the character for the job—notably dressing down Branislav Ivanovic in a fit of pique at West Brom—and talks well with officials.
But Cech is hampered by the limited involvement he has in play, being stuck at one end of the pitch.
It is often said that the best form of defence is attack and few prove that better than John Terry.
No defender in Premier League history has scored more goals from open play.
How often, when time was running out, have we seen Terry pop-up for a Chelsea corner—only to reel away seconds later having headed the ball home?
That aerial threat in the box, in particular, is something Chelsea lack when Terry isn't there. Branislav Ivanovic can do it, and Gary Cahill sometimes manages it, but neither gets into those dangerous attacking positions as regularly as Terry.
Chelsea miss the goals Terry scores almost as much as the ones he prevents opponents from scoring.