It was prompted more by his inconsistent form than his crash on a Pyrenean mountain descent which displaced two vertebrae, and left him in great pain.
"Big tours seem to be beyond me," he said. "I am a good enough single- day rider and for smaller stage races. I am 28 and I have to know what I can do.
"I shall be making a career review after this, but it doesn't have to be as drastic as it sounds. I just have to get people around me to accept what I can do."
Certainly, he wants to escape the pressure that being team leader incurs. "I took on the position of leader because it was open, but I may be better off as a No 2 or 3. Then I don't feel the pressure.
"The opening time trial is a hell of a lot of pressure. In seven and a half minutes you have to get everything out. That I can handle."
With his team sponsors, GAN, the French insurance group, quitting at the end of the year, Boardman may have to consider offers from other teams unless his current team manager, Roger Legeay, finds a new backer.
Among Boardman's problems is one that many riders would love to have. His career highlights since he won Olympic gold in Barcelona include a yellow jersey debut in the Tour in 1994, the world hour record in 1993 and 1996, and world titles in the 4,000 metres track pursuit (1994 and 1996) and the road time trial in 1994.
The next step up is huge. "It is only logical for people to expect more after what I have done," Boardman said.
"After that opening time trial any results would have been a bonus. Luckily Cedric [Vasseur] took up the reins, but it was like salt in my wounds."
Vasseur's valiant solo effort put Boardman's fellow GAN rider in the yellow jersey for four days, and that took the pressure off the Briton. He rode on in agony after his crash. "It was like a poker sticking in me for eight and a half hours. Each day after that I would ride saying: `I cannot carry on with this.' Yet still I kept turning the pedals."
Boardman has known Tour agony twice. In 1995 Britain expected much, but the twilight in Brittany turned into the twilight of his Tour. He crashed on a wet road in the opening time trial, and next day was flown home with fractures to a wrist and ankle.
Last year he announced that it was Paris or bust. He reached the French capital, but suffered with an internal bug that made life hard on a vicious stage to Pamplona. Such hardships made him work harder on being right for 1997.
"I could not have done any more than I did to prepare, and I was even two kilos lighter than the previous year," he said. "However, I was not happy with my form. It is so inconsistent, and now I am having blood tests to check it out.
"It is going to be a laborious search just to find the reason why I cannot maintain my form."
Now he is "dead set" on reaching Paris. "It is not in my nature to give up," he said. "I am one and a half hours behind the leader, but I am focusing on the positive."
One aim is success for Frederic Moncassin. GAN's sprinter has missed out in all the sprint finishes so far. "I will be trying hard to get Fred in a good position for a victory. I feel so sorry for him. He has been frustrated too often."
Meanwhile, Boardman is focussed on today's 55km mountain time trial at St Etienne. Before his tumble he would have been a real threat to the Tour leader, Jan Ullrich, but despite pain-killing tablets, acupuncture and physiotherapy, his injury stops him riding his special time-trial bike.
"I cannot ride in that position. In fact I cannot even put my hands in my pockets because of the torn muscles around my neck," Boardman said.
Ullrich is expected to romp home in the time trial, especially as Boardman is injured and some other real threats - Tony Rominger, Alex Zulle and Yevgeny Berzin- are all at home, nursing their broken collarbones.