Australia pace bowler Brett Lee [Images] is in hospital being treated for a knee infection and is rated 50-50 to play in the third Ashes Test against England [Images], starting in Manchester on Thursday.

Lee was feeling pain and swelling in his right knee, which he grazed while fielding in the first Test at Lord's and was admitted to hospital in Birmingham on Monday.

"He has been put on an intravenous drip giving him antibiotics," said Australia's physiotherapist Errol Alcott.

- Images from the second Ashes Test

"He is comfortable and will be kept in overnight.

"The doctors are confident he is going to respond but he won't travel to Manchester with the team tomorrow."

Asked about the likelihood of Lee recovering in time for Thursday's start of the third Test, Alcott said: "I can't really say, my answer is always 50-50."

BATTING HEROICS

Lee's batting heroics in top scoring with 43 not out in the second innings almost took Australia to an unlikely victory in the second Test on Sunday before England triumphed by two runs to square the series at 1-1.

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Australia look likely to again be without fellow fast bowler Glenn McGrath, who missed the Edgbaston defeat after twisting his ankle while warming up before the start of play on the first day.

McGrath was hobbling around Birmingham on Monday and though he has not been ruled out, the fourth Test of the five-match series at Trent Bridge starting on August 25 is a more realistic target.

"Glenn had another scan on Monday, he has got extensive ligament damage," said Alcott.

"But he's coming along well. Glenn is positive and I'm positive.

Before Lee's problem emerged, Australia had been toying with the possibility of playing a second leg spinner at Old Trafford, with Stuart MacGill the likely man to join Shane Warne [Images].