Villa's Richard Dunne still struggling to find his fitness

Villa were forced to apologise this month for comments relating to Ireland's medical care for the defender but Lambert admitted Dunne cannot shake it.

He said: "He's still struggling with injury which is a bit of a pain, we need to get to the bottom of that.

"He's had an operation but it's still underlying, not clearing up."

The injury – coupled with the sale of James Collins to West Ham – have seen Lambert field a youthful back-line with only summer signing from Feyenoord Ron Vlaar over 23.

But they kept their first Premier League clean sheet of the season in last week's 2-0 win over Swansea.

Right-back Matt Lowton, a £3m signing from Sheffield United, scored his first Villa goal while Eric Lichaj impressed again at left-back.

And Lambert believes the 23-year-old American can become a vital player in his new-look Villa side as he battles with Joe Bennett for his place.

The Villa boss said: "Eric's done great, the good thing about him is that he can play in a few positions and hasn't looked out of place at all," he said.

"He goes about his job and you always know what you're going to get from him which is a great trait.

"If he's talking about Joe breathing down his neck, then he's right.

"You have to try and keep him out, but that's the nature of the east, that's football and it's the same all over the world.

"As long as you keep having the competitive nature, and they want to drive on and be successful and make the club successful, then that's great."

Meanwhile, Lambert confirmed Samir Carruthers has been fined for using his mobile on club time.

The winger posted a picture on Twitter of £500 after he was reprimanded by the Villa chief.