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.
The Spaniard was being treated in Barcelona.
West Ham United vice-chairman Karren Brady suggests that the club may not spend money in the January transfer window.
The West Brom forward has most strongly been linked with Tottenham Hotspur.
Southampton went down 2-1 to Crystal Palace in the FA Cup on Saturday afternoon.
Leeds United beat Rotherham 2-0 at Elland Road today.