One of William Fox-Pitt's elite horses, Cool Mountain, will miss the Olympic Games due to a tendon injury.
Fox-Pitt won the Rolex Kentucky title in 2010 and Great Britain team gold at the 2010 World Championships with Cool Mountain.
The 43-year-old does have two other elite standard horses in competition; he won the 2011 Burghley Horse Trials on Parklane Hawk, while riding Oslo to glory at the Stars of Pau event.
"It is particularly sad to have Cool Mountain off this year," said Fox-Pitt.
"He has done incredibly well, and in a way he was my banker. That was the horse I thought I would be riding.
"He injured a tendon in Germany last year. It's not very serious, but I am going to give him a whole year off. That would give him the best chance of recovering for the future."
Fox-Pitt, who heads for London 2012 having competed in three Olympic Games, is the only rider in eventing history to win five four-star events - Badminton, Burghley, Kentucky, Luhmuhlen and Pau.
He collected silver at Athens 2004 and bronze at Beijing four years later and has vowed to keep his preparations for London as normal as possible despite being swept up in the excitement of a home Olympics.
"It is important for me to remember that I have ridden in three previous Olympic Games, and this is just another one," Fox-Pitt said.
"But, having said that, it is quite hard to keep that in perspective because London is something that has really focused the mind for a long time.
"It has been a target, and then suddenly you find yourself in 2012. I think the challenge is going to be to try to be as normal as possible, get selected and then be in one piece at that time.
"All three have got strengths and weaknesses, but they are looking promising at this stage. They are very good horses mentally and they are very confident, and I think that will count for a lot.
"I am very lucky to have three horses in contention. Oslo and Lionheart I've had right from novice level, and Parklane Hawk has really stepped up to the mark."
