Dunne has been unavailable since picking up the injury at Euro 2012, and three operations have yet to cure the problem.
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But Lambert knows the Republic of Ireland international must not be rushed back to competitive action, despite Villa being embroiled in a relegation battle and the player’s contract expiring this summer.
“Is it career-threatening? No, nothing like that. You can't say that,” the Villa boss told ESPN.
"But there are little niggles that aren't clearing up. That's a real frustrating thing for him.
"Richard has been trying his utmost to get back fit. He's been to the best people on the other side of the world.
“He feels good at some points, but not so good at other times. He can't play through the pain barrier with that injury."
Dunne joined Villa in 2009 and has made 95 appearances for the Midlands club.