Beckford has bagged 19 goals so far this season and manager Gary McAllister admitted that he would be a 'big loss' over the next few weeks.

"Jermaine's performance levels have moved up this season. He is a finisher and he scores all types of goals," said McAllister. "He's got a slight tear in his hamstring and we're giving it a week to settle before he has any scans but at the moment it's not looking good.

"He's a fit lad and that's a big thing, but I would think it is a minimum of three or four weeks."

Leeds, who visit Histon in the second round of the FA Cup on Sunday, slipped out of the League One play-off zone when suffering a fifth defeat in 10 league games at the Sixfields Stadium.

Beckford's absence may provide an opportunity for former Derby County striker Malcolm Christie, who has signed for Leeds on a non-contract basis but missed the last two games with a rib injury.

Lucciano Becchio and Enoch Showunmi are the only other out-and-out strikers at the club but Robert Snodgrass and Andy Robinson can also play in attack.

McAllister, meanwhile, was keen to strengthen his defence yesterday but failed in a move for Hull City defender Wayne Brown who had only just returned to the Premier League club after a loan spell at Preston.

According to Hull manager Phil Brown, Leeds wanted the 31-year-old on loan until the New Year but offered no guarantee of a permanent deal.

"Wayne has rightly said that, at 31, he doesn't have to go on trial anywhere," said Hull's manager.