Watford manager Malky Mackay's plans for the second half of the season have received a big boost after Henri Lansbury's loan was extended for the remainder of the campaign.

Although the Hornets had been confident of securing the services of the Arsenal midfielder, the move was not given the green light until Lansbury had successfully concluded his contract negotiations with Watford's training ground neighbours.

But the deal, which came after this week's deadline for the printed issue of the Watford Observer, has been finalised in time for the England Under-21 international to face Chelsea on Sunday if he is fit to play.

Lansbury is a concern for the FA Cup third round tie at Stamford Bridge after sustaining a heavy knock on the ankle during Monday's 2-2 draw at Bristol City, although it is understood the injury is unlikely to keep him on the sidelines for too long should he be ruled out of the tie.

Watford are also continuing negotiations with Queens Park Rangers in their attempts to keep Heidar Helguson for the rest of the season, but it appears increasingly unlikely that a deal will be finalised in time for him to face the FA Cup holders and Premier League leaders.