The Italy Under-21 international was removed from the senior pecking order during the summer, the expectation being that he would be sold or loaned elsewhere.
Instead, a suitable offer did not arrive for the former Inter Milan starlet and he has subsequently been reintegrated back into the first-team fold.
With Romeo Lavia not back from injury during the early part of last week, Casadei played the full 90 minutes as the Blues thrashed Barrow in the EFL Cup third round.
Lavia is also absent from Europa Conference League fixtures until at least February, a consequence of Maresca wanting to manage the Belgium international's fitness after he missed the majority of 2023-24.
As a result, Casadei finds himself in prime position to finally be handed a run of starts in a Chelsea XI, over two years on from leaving San Siro for Stamford Bridge.
What has Maresca had to say?
Speaking to reporters ahead of Thursday's fixture against Gent, Maresca has indicated that the 21-year-old will be given opportunities to impress in what will be an unfamiliar defensive-midfield role compared to his previous experiences in the engine room.
At a press conference, the Italian said of his compatriot: "I think Cesare did very well in that game (Barrow). He struggled at the beginning, but at the end, he finished very well. We can see Cesare there again, for sure.
"The idea, I think, he can cover different things. Physical things, he can pass, on the ball, off the ball, understanding how he has to move, he can give us good things.
"I was happy the other day and, for sure, we are going to see him again in that position."
When quizzed on a change of role for Casadei, Maresca added: "Cesare is more box to box, he likes to attack and arrive in the box. I had Cesare at Leicester so I work with him already many months, but he can also do the other part.
"Give balance to the team, stay in that position and don't move from there. Help your teammates in the build-up. Help your teammates when you need to defend. I think he can do that."
A big step up?
For a player who cost €20m in 2022, Casadei is in desperate need of minutes at Chelsea, even if they do not come in the Premier League.
Aside from the 71 minutes that he accumulated across 11 substitute outings during the second half of last season, Casadei has no senior experience in a top-flight league.
Casadei does have 21 starts and 16 substitute appearances in Championship fixtures with Reading and Leicester respectively, a further three starts coming in cup competitions.