Vardy could make just his second start of 2022 on Thursday night in the Europa Conference League semi-final first leg against Roma after recovering from a knee injury.
"Jamie is a legend," Castagne said. "He can score everywhere and find space so easily. Of course I'm not throwing shade at Patson or Kele but with Vardy you just need one look with him and he's gone.
"Hopefully we don't rush him either because if he gets injured that would not be good for us. He's in a good place now.
"He still looks good even when you see him sprinting in training you don't think he's 35. He still has that spring to him. Hopefully we will see more of him.
"It's very good. Everyone knows his quality. We want to have every player fit and it's another who's come back and for sure we'll be stronger with him."