Castleline is currently at League One outfit Shrewsbury Town, where he moved on loan in the summer.
He is hoping that loan spells will give him the experience to be able to compete for a Chelsea start in the coming years.
Speaking to football.london, Castledine said: "I think it's been really positive, not for me personally but even as a team.
“We struggled at the start of the season, it was tough the first couple of games and it didn't go as planned, but I have always thought there was a foundation in the team. And with the right leadership and mentality going forward I can't see any problems."
"I think I have done alright," he added, when asked about his own displays.
"With it being my first loan my main focus was to come here and do as well as I can, show who I am as a player as a personality, stay in the team as much as I can and help the team as much as I can as well."
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