West Ham United won 1-0 against Wolverhampton Wanderers in the FA Cup on Saturday afternoon.
Rangers midfielder Jason Holt is rated highly by Barry Ferguson.
Nottingham Forest knocked Queens Park Rangers out of the FA Cup on Saturday afternoon.
Grealish missed Saturday's 1-1 FA Cup third round draw at Wycombe Wanderers with tonsillitis, while Richards was forced off in the closing stages of the match after injuring his foot.
Newcastle United went down 1-0 to Watford in the FA Cup on Saturday afternoon.
The Leeds head coach has been discussing the 24-year-old following his side's FA Cup win over the Millers.
Manchester United won 1-0 against Sheffield United at Old Trafford in the FA Cup on Saturday evening.
The former Premier League defender has praised the Aston Villa captain.
West Ham United beat Wolverhampton Wanderers 1-0 in the FA Cup today.
The Portuguese talent turns 23 this month.