The incident followed an attack from Aru on the Mont du Chat when yellow jersey Froome had his hand in the air to indicate he had a mechanical problem.
Aru attacked passed him and, without cooperation from the others and Froome speeding back with his team-mates, eased up.
In a right-hand hairpin afterwards, the three-time British winner of the Tour swerved towards Aru and forced him close to the fans on the right to avoid falling.
“Once I got back to the group I think the very next hairpin we went round I lost my balance a little bit and swerved to the right,” Froome said during Monday’s rest day.
“Aru happened to be on my right and he had to swerve as well. It was a genuine mistake and I think Fabio was the first to recognise that. I apologised straight away on the road as soon as it happened.
“Any suggestion that it was on purpose is just crazy – first of all it’s not anything I would ever do, and I was already on my spare bike, so to risk putting my derailleur into Aru’s front wheel. It’s just crazy. I wouldn’t risk that at all.”
Some speculated that Froome was trying to pay back Aru for attacking Froome when he clearly needed assistance.
The Italian from Sardinia gave a similar explanation to Froome’s outside his team bus after stage nine when asked about it.
“He was almost falling because he’d come close to a fan, he lost his balance and the elbow came out for balance,” Aru said. “Actually, he said sorry, it wasn’t on purpose, no way.”
Aru, winner of the 2015 Vuelta a España, also played down the earlier incident when he attacked.
“I didn’t see it because I was attacking, I wanted to attack from far out,” Aru continued.
“We were fine from there to the finish. He saw that I stopped so he didn’t have any problem.”
Simon Yates (Orica-Scott) and Daniel Martin (Quick-Step Floors) were concerned with Aru’s aggression. Martin said that he is not sure Aru knew and told him not to attack. Yates called Aru’s excuse “absolute bulls***.”
“Obviously there was also the incident out on the road where I had a mechanical on the Mont du Chat,” added Froome. “It was clear to me I had to change bikes straight away and it appeared that Fabio Aru accelerated at that moment.
“I think certainly in the peloton there’s a bit of an unwritten rule that when the race leader has some kind of an issue that prevents him from racing, then the group doesn’t take advantage of a situation like that.
“So I’m really grateful to them for sitting up and easing the pace for a few moments while I was able to change the bike and get back. I think Richie was instrumental in that so, again, thank you to Richie for that.”
It is unclear if Froome spoke to the Aru about his attack during the aeroplane trip to Périgueux on Sunday night or during the rest day.
He said after the stage, “We will have to see what Aru has to say about it. I’ll certainly ask him about it when I see him.”
Froome leads the race by 18 seconds over Aru and 51 seconds over Romain Bardet (Ag2r La Mondiale).