Manchester United face rivals Manchester City in the league on Sunday . Robin van Persie has missed United 's last 24 games through injury . 31-year-old striker has scored 10 goals in six league games this season . United have won their last five league matches , climbing up to third . Rio Ferdinand : Wayne Rooney up top is reason behind United 's good form .
Manchester United face rivals Manchester City in the league on Sunday . Robin van Persie has missed United 's last six games through injury . 31-year-old striker has scored 10 goals in 24 league games this season . United have won their last five league matches , climbing up to third . Rio Ferdinand : Wayne Rooney up top is reason behind United 's good form .