The 47-year-old said that he is looking to improve all areas of the pitch ahead of the new season, but believes that his team is well stocked and will not be rushed into making purchases.
"We're coming at it from a position of strength, because we've got [Richard] Keogh and [Jake] Buxton, who have proved themselves to be a more than adequate centre-half pairing," he told the Derby Telegraph. "We've got to get a better centre-half than Jake, which will not be easy.
"We've got Mark O'Brien coming back from injury around September time and Shaun Barker not too far behind him. We've also got Valentin Gjokaj, who deputised a couple of times last season and didn't let us down, even though he wasn't even playing in his usual position.
The Rams finished 10th last season.