Hughes became a victim of the Etihad structure in 2009 when he buckled under the pressures exerted by owner Sheikh Mansour.
City's Champions League campaign now hangs in the balance following a 2-0 midweek reverse to Barcelona, and Hughes believes a lack of progress will cost Pellegrini dearly.
Hughes, who returns to Eastlands on Saturday as manager of Stoke, offered Pellegrini a direct warning of the tenacious demands of Mansour.
"He's shown progress this year," Hughes told the Daily Mirror. "I don't think they'd qualified for the latter stages before.
"Roberto Mancini wasn't able to do it but they've done it quite comfortably. That's progress I think. As long as he's seen to be progressing the team and the club, then he'll be fine.
"They are strong owners and demanding owners, so it's no different from anyone else in that regard. You have to get the results that the ownership require.
"They have a definite view in terms of what they expect for the investment they've made, and they will want to see the club progressing."
Although Hughes believes a lack of progress could pose an immediate threat to Pellegrini, the Welshman claims City are laying the foundations for lasting success.
"I'm looking from the outside in these days, but you see the progress they're making off the field and that's the huge thing," he added.
"Once everything is in place - in terms of infrastructure, academy and stadium - you can see they'll be successful for a hell of a long time.
"It's exciting times for them and the coach in charge has obviously got to maintain the progress on the pitch as the ownership maintains the progress off the pitch."