Watford have goalscoring midfielder John-Joe O'Toole back from a ban and loanees Gavin Hoyte, Jack Cork and Liam Bridcutt are all available to play. Lee Williamson is fit again and winger Lionel Ainsworth could figure after he returned from a loan spell at Hereford. Crystal Palace boss Neil Warnock may tinker with his defence, with one of Matt Lawrence and Jose Fonte making way and Clint Hill moving into the middle. Danny Butterfield could play but Ben Watson is set to leave Palace. Watford and Crystal Palace lock horns at Vicarage Road in one of the three all-Championship fourth round ties. These clubs are meeting in the FA Cup for the second successive season. Daniel ****tu scored both goals in the Hornets' 2-0 home win in last year's third round. Watford have only progressed beyond the fourth round twice in 13 years, and on both occasions they reached the semi-finals.
Crystal Palace have not won any of their last four away ties in the FA Cup, and have lost three of them.
Watford lie 11 places lower than Crystal Palace in the Championship table.
Referee: Michael Oliver (Northumberland)
Won one of six in all competitions; that victory coming in the third round of the FA Cup. Grzegorz Rasiak's goal from the 1-0 home win over S****horpe in round three was their only score in four league and cup matches. Victory here will make this their best performance in the competition since 2007, when they reached the last four. Brendan Rodgers holds a 100% FA Cup record as a manager; won one of one. It's 25 years since the Hornets enjoyed their finest hour in the competition by going all the way. Graeme Sharp and Andy Gray scored in a 2-0 victory for Everton in the Wembley showpiece, to end what had been a dream run for Graham Taylor's side, culminating in the tears of chairman Elton John. These clubs opened the season with a goalless draw in the Championship fixture at Selhurst Park on 9 August. Palace won their last visit to Watford 0-2 on 14 April last season, when Paul Ifill and Victor Moses were on target. This is the fourth time these clubs have been drawn together in the FA Cup; Watford lead by two wins to one.