Two years ago, Papy Djilobodji and Michael Hector were added to the squad. With neither ever making a single Premier League appearance for the club, it is fair to say that they did not create the impression that then manager Jose Mourinho was expecting. Last season, the services of David Luiz were secured at the 11th hour but the deal still represented just one new face in a part of the team that seemed ageing and slow.

Perhaps the reason for the absence of central defenders being linked with a switch to West London this summer is due to it being arguably the best functioning area of the side. Although Chelsea struggled to shut out the opposition in the final few months of the campaign, the run of 16 games between the beginning of October to the end of January, that saw only four goals conceded, laid the foundation for their title-winning campaign.

Rather than being conventional and predictable, Chelsea's back three proved to be diverse and complementary. Gary Cahill brought some rugged physicality to the side that John Terry had previously made his trademark along with aerial prowess in both areas and an eye for goal. Cahill netted an impressive six times in the league, including some vital strikes such as the late winner in the 2-1 victory at Stoke and a goal on the stroke of half-time in a must-win game against Southampton at the end of the season.

Luiz slotted into the central role as if he was born to play there. Instructed to orchestrate the play from deep when in possession, he was also afforded license to make the occasional foray forward. Defensively, his brief was to read the play in front of him and cover for any mistakes by his teammates, something he executed brilliantly. Cesar Azpilicueta, meanwhile, continued to show his versatility with his ability to anticipate and snuff out danger proving to be even more effective as a right-sided centre-back than at full-back.

But as impressive as all three of them were during Chelsea's march to glory, this is not time for the club to rest on their laurels. For a start, both Luiz and Cahill are now into their 30s, so the clock is ticking. Modern fitness and nutrition regimes can see players, especially in defensive areas, nurture their career for longer than in days gone by, though it makes sense to plan for the future in any case.

There is also the need to supply competition for places. While the disaffection between Mourinho and some members of the squad was often blamed for the ill-fated title defence of 2015-16, that most players were operating in the knowledge that there were no viable alternatives for their position meant that motivation was inevitably low. It therefore makes sense to place some pressure on even the biggest stars at the club so that any complacency is eradicated.

Juventus' Leonardo Bonucci is the only central defender of note to have been linked with a switch as yet, with a falling out earlier in the season with manager Massimiliano Allegri being cited as mitigation for the rumour. But being 30 years old, having signed new terms in December with a Champions League finalist and commanding an astronomical transfer fee, it can be assumed that a deal is highly unlikely to materialise.

Perhaps, then, Chelsea are considering the previously unthinkable and actually deciding to promote from within. The talent is certainly there. Nathan Ake was hugely impressive during his loan spell at Bournemouth, so much so that Antonio Conte recalled him for the second half of the season. His performance in the FA Cup semifinal win over Tottenham was particularly eye-catching, and having been on Chelsea's books since 2012, he has paid his dues.

Another player to have made a decent case for future involvement is Andreas Christensen. Having spent the past two years gaining valuable first-team experience in the Bundesliga and Champions League with Borussia Monchengladbach, the 21-year-old Dane has confirmed that he will be returning to his parent club and joining the first-team squad on their summer tour of the Far East.

And then there are Chelsea's U20 World Cup-winning heroes, Fikayo Tomori and Jake Clarke-Salter, the centre-back partnership that anchored the England defence during the recent triumph in South Korea. Still only 19, they might still be a little too green to feature on a regular basis with further loan moves almost certainly planned for them. However, they have both already made their senior debuts for Chelsea to hint at a bright future for them and their club.

Chelsea's meagre record at taking risk on young talent is well documented. But maybe, just maybe, the work of the club's all-conquering development squads might finally be about to bear fruit.