Redfearn is yet to sign a full-time contract with the Championship outfit, but he is likely to do so in the coming days.
The 49-year-old Englishman is a popular figure among the Leeds fans and is being backed to eventually take the Whites back to the Premier League.
However, 21-year-old Ralls has admitted that he has not got much knowledge about Redfearn as Cardiff prepare to face Leeds in the Championship on Saturday.
Ralls, though, fully understands the threat that Leeds pose and reveals his respect for the former Premier League outfit.
‘We know Leeds are a big club, but on the day it’s eleven versus eleven’, the youngster told Cardiff’s official website. ‘We believe we can get the three points.
'I think with Leeds, you always know they’re going to be a strong side. It’s going to be a tough game like it always is against Leeds – they’ll bring good fans down here, they’re a big club.
‘They’ve got a new manager up there which I don’t know a lot about, so in that respect there’s a bit of uncertainty, but for us it’s just about making sure we’re right, and that we perform on the day’.
Cardiff are currently 11th in the Championship table with 19 points from 14 matches, while Leeds are three points behind them in 18th.