Newcastle sit ninth in the Premier League and are safe from relegation, but the club have endured a turbulent season under Pardew's leadership.
The 52-year-old was banned for seven games by the Football Association after headbutting Hull City's David Meyler in March.
Newcastle owner Mike Ashley backed Pardew following the incident at KC Stadium.
But Shepherd, who stepped down from his role in 2007, says the former West Ham boss is unlikely to have survived under his leadership.
"I think the board at the time, not particularly me, with Sir John (Hall) would have had him on his bike," Shepherd told the Chronicle.
"Who knows the emotion he was going through?
"I like the guy. I've met him and in normal circumstances you'd certainly have a pint with the guy, he's fine.
"I think he just lost it that day.
"Would he have survived if he was at Man U or Chelsea or Liverpool as boss? I doubt it."
