Britain's Mara Yamauchi has been ruled out of this year's Virgin London Marathon with a hamstring injury.
The Japan-based runner was hoping for a return to form after two disappointing performances in 2010, in London last April and at the New York marathon in November.
But with the London 2012 Olympics on the horizon, Britain's main hope for the race on 17 April has been forced to concentrate on treatment and rehabilitation.
She said: �"I am very disappointed to have to withdraw from the 2011 Virgin London Marathon due to a hamstring injury. London is an iconic marathon which I have enjoyed racing many times.
�"I was looking forward to returning to London this April. But my injury treatment and rehabilitation must take priority, especially with the 2012 London Olympics approaching fast.
�"I hope to return to my best as soon as I can. I wish everyone who competes on 17 April the best of luck."
Yamauchi was one of 15 women announced in the elite line-up who have a marathon best of less than two hours 25 minutes. She set her personal best of 2:23:12 when finishing second to Germany's Irina Mikitenko in 2009, a performance that appeared to herald a breakthrough for the former diplomat. But a series of injuries have prevented her reproducing that form since.
She missed the 2009 World Championships in Berlin with a foot injury and could only finish 10th in London last year exhausted by a six-day journey from her training base in the United States caused by Iceland's volcanic ash cloud.
She skipped last August's European Championships in Barcelona but lined up for the New York Marathon on 7 November with high hopes of finishing in the top three. After racing with the leading group for the first half of the race, she faded to finish 13th in 2:31:38.
Virgin London Marathon race director Dave Bedford said: �"It is a hugely disappointing to lose Mara from this year's race. Many in Britain were hoping to see her up with the medalists again, as she was two year's ago.
�"It is a bitter blow for her, but we understand she needs to recover fully from this injury and prepare as well as possible for the Olympics next year.
�"Despite Mara's absence, we still have one of the most talented women's fields ever for this year's Virgin London Marathon and are looking forward to a fantastic race."
Britain's hopes in the women's event now rest with Olympian Liz Yelling, the former Commonwealth Games bronze medalist, plus two marathon debutantes, Yelling's sister-in-law Hayley Yelling, and seasoned international Jo Pavey.
Andrew Lemoncello will fly the flag for Britain in the men's race. The Scotsman was eighth on his debut last year.
The following is a full list of the men's and women's elite entries for the 2011 Virgin London Marathon.
Elite athletes and their best marathon times
Tsegaye Kebede ETH 2:05:18
Patrick Makau KEN 2:04:48
Samuel Wanjiru KEN 2:05:10
Abel Kirui KEN 2:05:04
Bazu Worku ETH 2:05:25
Jaouad Gharib MAR 2:05:27
Emmanuel Mutai KEN 2:06:15
Viktor Röthlin SUI 2:07:23
Abderrahime Bouramdane MAR 2:07:33
Yonas Kifle ERI 2:07:34
José Manuel Martinez ESP 2:08:09
Marilson Gomes dos Santos BRA 2:08:37
Dathan Ritzenhein USA 2:10:00
Dmitry Safronov RUS 2:10:12
Dylan Wykes CAN 2:12:39
Cuthbert Nyasango ZIM 2:12:40
Jason Lehmkuhle USA 2:12:54
Mike Shelley AUS 2:13:05
Michael Aish USA 2:13:21
Andrew Lemoncello GBR 2:13:40
Collis Birmingham AUS Debut
Stephan Shay USA Debut
Patrick Smyth USA Debut
Mohamed Trafeh USA Debut
Liliya Shobukhova RUS 2:20:25
Zhou Chunxiu CHN 2:19:51
Irina Mikitenko GER 2:19:19
Constantina Dita ROU 2:21:30
Askale Tafa ETH 2:21:31
Inga Abitova RUS 2:22:19
Lornah Kiplagat NED 2:22:22
Aselefech Mergia ETH 2:22:38
Bezunesh Bekele ETH 2:23:09
Bai Xue CHN 2:23:27
Mariya Konovalova RUS 2:23:50
Xiaolin Zhu CHN 2:23:57
Aberu Kebede ETH 2:23:58
Yukiko Akaba JPN 2:24:55
Edna Kiplagat KEN 2:25:38
Magdalena Lewy Boulet USA 2:26:22
Liz Yelling GBR 2:28:33
Lisa Weightman AUS 2:28:48
Mary Keitany KEN 2:29:01
Fiona Docherty NZL 2:32:17
Tanith Maxwell RSA 2:32:33
Jo Pavey GBR Debut
Jessica Augusto POR Debut
Nikki Chapple AUS Debut
For more information contact the Virgin London Marathon Press Office:
Nicola Okey 020 7902 0182 / 07799 661345; email@example.com
Hannah Finch 020 7902 0199; firstname.lastname@example.org