Phillips Idowu apologised for pulling out of the triple jump at the Aviva London Grand Prix - just three days after insisting injury was not behind his long lay-off this season.
Olympic silver medallist Idowu has competed just three times in 2012, with his last appearance coming in Oregon on June 1, when he took three jumps before sitting out the rest of the competition. The 33-year-old subsequently withdrew from meetings in Oslo and Paris and the Olympic trials in Birmingham.
UK Athletics head coach Charles van Commenee declined to clarify Idowu's situation due to issues of "medical confidentiality". Idowu claimed he had never mentioned an injury and was happy to let the "rumour mill stir itself", but pulled out of the competition at Crystal Palace just 25 minutes before it was due to start with a hip problem he felt while warming up.
He wrote on Twitter: "Hey guys, sorry to have to pull out of #ALGP, slight bit of muscle tightness. I will be fine in a day or 2. Hope the other jumpers put on a great show for you. See you 7th aug. thanks for your support."
August 7 is the date of triple jump qualifying at the London Olympics, meaning Idowu has just 23 days to get himself in top shape.
The Londoner said he pulled out of the competition in Oregon because slipping on the wet board had put "the fear of God" into him, and Jonathan Edwards felt Idowu probably "didn't fancy" facing similar conditions in London.
"When I turned up at the track this morning, I asked myself 'Would I have wanted to jump today?' and the answer was no," the former Olympic champion and world record holder said on the BBC.
"Phillips probably didn't fancy it, but there is nothing to worry about. It's cold, damp and he doesn't want to take any risks. We will forgive him everything if he jumps well in London."
Ross Murray was an impressive second in the Emsley Carr mile in 3:52.77, while hurdles specialist Jack Green won the national 400m flat race in 45.99, a second personal best in the space of 24 hours.
Green was not thrilled with the time but added: "I won the race though and beat the two guys in the relay pool so hopefully that stands me in good stead for the 4x400m relay in the Olympics."