The arrival of experienced Brazilian centre-back Thiago Silva has bolstered a Chelsea defence that was often flaky last season, but his signature, along with the signing of France U21 international Malang Sarr, could see some current blues defenders moved on.
One defender who finds himself at risk of this is 22-year-old Fikayo Tomori.
The academy graduate looked to have become a regular in Frank Lampard's side during the first half of last season, making 14 Premier League appearances before January, but injuries and a drop in form have seen him make only one league appearance since.
His potential is undeniable, Lampard worked with him at Derby County before moving to the Stamford Bridge hot-seat, and trusted the young defender to perform against some of the best attackers in Europe.
His faith was repaid, but with Tomori dropping down the pecking order, prior to the addition of two talented centre-backs, his future in West London and place in Lampard's plans is far from secure.
Pacey and sharp on the ball
The most important question to ask is whether Tomori still has something to offer Chelsea. The answer is yes. During the first half of the season, the defender demonstrated an ability to bring the ball forward from defence that surpassed all of the others in his position, bar Andreas Christensen, potentially.
Having worked under Lampard at Derby and Chelsea, Tomori is well accustomed to the way the manager wants to build out from the back with his defenders and he looks far more comfortable bringing it forward than Kurt Zouma, who is more traditional in many ways.
One thing the two defenders share is recovery pace. While it is true that the better a defender is, the less often he will need to rely on his pace, when facing quick forwards like Mohammed Salah and Raheem Sterling. The 22-year-old was deployed as a full-back at Arsenal last season, so he also offers the blues versatility.
A loan spell on Merseyside
At the moment Tomori looks to be nearing a loan move to Carlo Ancelotti's Everton and a very exciting project with the additions the Toffees have made in the last few weeks.
Zouma spent the 2018/19 campaign on the blue half of Merseyside and came back a more reliable defender, worthy of a regular place in Lampard's starting XI.
The move could have the same effect on Tomori who has plenty of youth on his side, and the opportunity to play week-to-week at a strong Premier League side managed by one of football's greatest head coaches could hardly be bad for the young man.
With Silva expected to partner either Zouma or Antonio Rudiger at the heart of Chelsea's back four this season, Tomori needs a temporary move to continue to develop at the highest level.
Silva is fast approaching his 36th birthday and Rudiger is less than three years away from his 30th so it goes without saying that players like Tomori, Zouma and Sarr are the long-term future of this Chelsea side under Lampard.
The manager will definitely want to see Tomori become an integral part of the backline at Stamford Bridge in years to come, but as things stand a spell away is the best course for him to take.