Cesare Prandelli highlighted Valencia's inability to sign striker Simone Zaza as the reason behind his exit from the LaLiga club.
Prandelli resigned as Valencia head coach after just three months in charge in late December, accusing the team of being run by "numbers people".
Prandelli also hit out at Valencia for their failure to guarantee the reinforcements he requested, after senior club officials accused the former Italy boss of "giving up and abandoning ship".
And Prandelli took aim at Valencia again, with the Italian telling SER Deportivos Valencia: "I felt undermined.
"I arrived at a big project and left with a poor impression.
"Why is Zaza not here? I do not know. But on the 28th, the president told me I had 24 hours to choose between a striker and a midfielder and that for me was not a progressive move.
"I think some an outside counsellor advised [owner] Peter Lim no to sign him."
Valencia are languishing in 17th position, above the relegation zone on goal difference amid a seven-match winless streak in LaLiga.
In a statement of concern for Valencia fans, Prandelli added: "Some players have told me they are afraid to play in Mestalla."
Valencia host Celta Vigo in the Copa del Rey on Tuesday before facing Osasuna in LaLiga on January 9.
