The Briton endured a miserable 2014 season with the Italian team, managing just one podium finish on his way to 13th in the MotoGP standings.
Crutchlow subsequently agreed to cancel his contract early after just one season and announced a move to LCR Honda in August.
The 29-year-old stated that a crash in Austin last April, which left him sidelined with a hand injury, badly affected his confidence and played a part in his failure to adapt to the Ducati bike.
"I don't think it was just the bike. I'd be the first to admit I wasn't riding it that well," Crutchlow told Autosport.
"It was only after my crash at Austin - up until then I felt confident. I think it's probably one of the biggest crashes of my career.
"After that I wasn't willing to push and take risks as much as I had before until I got my confidence back.
"It took me a long time to get it back because I had no real feeling for or understanding of the bike."