Following the departure of Didier Drogba in 2012, the remaining three members who comprised the spine of Chelsea's formidable 2000s team must be released from Stamford Bridge at the end of the season.
Saying goodbye to loyal, long-serving club legends is a thankless and immensely difficult task for any manager. But it's also an important part of the job.
Former Manchester United boss Sir Alex Ferguson was the master of moving on players once they could no longer produce what the club demanded of them. Regardless of whether he liked them because they were both loyal and hard-working individuals, they would have to go if it benefitted the team.
Jose Mourinho will need to be similarly ruthless with John Terry, Frank Lampard and Petr Cech at the end of this season.
Terry, the club's inspirational captain, turns 33 next month. There's no denying he's been an excellent servant to Chelsea, but he's become increasingly injury-prone in recent years, while his severe lack of pace is also a hindrance.
Lampard, meanwhile, is arguably the best player in Chelsea's history. Last season he became the club's all-time top scorer before signing a deserved one-year contract extension, just when it looked as if he'd be heading off to the USA to sign a lucrative deal with a MLS side.
The England international will have turned 36 and played at the World Cup finals in Brazil by the time Chelsea reconvene for the start of the 2014/15 campaign, by which point the Blues may or may not have said their thank yous and goodbyes to the prolific attacking midfielder.
Lampard isn't the all-action player he once was, and Chelsea must look to the future. That means either bringing in another quality central midfielder - such as Real Madrid's Xabi Alonso - or giving the likes of Nathaniel Chalobah or Marco van Ginkel a chance to prove themselves as worthy successors to the man who will always be warmly referred to as "Super Frank" by the Blues' faithful.
However, the hardest decision Mourinho will need to make will inevitably involve his two goalkeepers. Petr Cech is still a top-class 'keeper, but the Czech Republic international will need to leave the club at the end of next season in order to make room for the supremely talented Thibaut Courtois.
The Belgium international is too good not to start for Chelsea next season. He may only be 21 years old, but you would never guess it by watching the 6ft 6in shot-stopper in action.
If Mourinho tells him he's still not ready to replace Cech next season, then there's a good chance that the Bree-born goalkeeper will seriously consider his future at Stamford Bridge. And as he would walk into every team in world football, Chelsea simply can't afford to take such a massive risk.
Why not keep the pair of them at Stamford Bridge, I hear you cry. Well, neither will want to sit on the bench - they're both far too good for that - which means there's only enough room at the club for one of them.
Courtois, on account of being ten years younger than Cech and just as talented, must get the nod.