CHRIS Judd is set to return to training in two weeks' time after successful surgery on his troublesome Achilles.

But the news is less promising for highly rated youngster Sam Docherty, who is set for more than a month on the sidelines after having surgery on his quad.

Carlton courted Docherty from the moment he announced he wanted to leave the Brisbane Lions and secured the 20-year-old in last year's trade period.

Blues football manager Andrew McKay said it was a disappointing setback for Docherty.

"It wasn’t improving at the rate we would like, so he went in to have surgery a couple of days ago," McKay told Carlton's website.

"They found some floating bodies behind his kneecap, so they removed those, and the surgeon believes that was what was causing the pain rather than the quad tendon.

“He’ll be back playing in four or five weeks."

The Blues are confident utility Lachie Henderson, who had a minor procedure on his illiotibial band last week, is on track for round one.

Carlton is also hopeful ruckman Matthew Kreuzer (knee) will be able to get some game time later in the NAB Challenge before returning early in the regular season.