Geraint Thomas conceded his Tour de France preparations have been impacted by his crash at the Giro d'Italia in May.
The Team Sky rider collided with a parked police motorbike during the ninth stage of the Grand Tour and ultimately had to quit the race, having been in contention to win it.
He has since been trying to recover full fitness while training in Monaco and previewing some of the forthcoming Tour stages with team leader and reigning champion Chris Froome.
But the 31-year-old revealed he was not yet back to his best, with the Tour starting on Saturday.
"I don't feel quite like the same as before the Giro," he told Cycling Weekly.
"In Trentino [Tour of the Alps ahead of the Giro], I felt like I was all prepared and ready to go, in Route du Sud [June 15 to 18], I was still on my way back up.
"It's taken a while to heal up, I've healed up properly, but still have to do physio exercises and stuff. It's definitely a different sort of run in to the Tour compared to the Giro.
"In the Giro, I was confident that I was feeling the best I had and ready to go. This time, I'm starting to get my way back up. I think once we get into the race it'll be fine."