Simone Zaza has told an Italian newspaper he could not adapt to West Ham’s training methods during his ill-fated loan spell at the club.
Zaza played only 11 times for the Hammers after signing from Juventus and failed to score.
A further three appearances would have triggered an automatic £17m permanent move, leaving the player in limbo from November.
The deal was terminated last month and Zaza has since joined Valencia on loan.
Speaking to Gazzetta dello Sport, the 25-year-old said of his time in England: “I didn’t feel great in so many ways: environment, culture, training, nutrition.
“I was not good physically. I had been through pre-season with Juventus so I was okay.
“When I got there [West Ham] I found a different method of training – you exercise less, sometimes the sessions last 40 minutes and almost immediately I didn’t feel good.
“I need to train more, for someone to kick my ass. The problem is that on Sunday other people went to a thousand percent. Not me.
“I wanted to do things that come naturally when I’m playing well and I could not do them. And I became crazy.
“I’m not being a victim, I know that plying your trade as a footballer allows you to earn so much.
“I’m just trying to explain the causes of my failure. I knew I’d find some difficulties, but I did not think there could be so many. I do not blame anyone – 99 per cent of it’s my fault because I was not able to adapt.
“I was sure that I’d make it, but it was probably because I’m set in my ways. I’m attached to my habits, my things, my points of reference otherwise I’m lost and I can’t find myself.”