Williams, 32, aggravated the strain during Wednesday's loss to the Boston Celtics, when he played only 10 minutes. He had missed the previous four games.
Nowitzki, 38, has been hampered by the sore Achilles since the season opener. He has played only three of the Mavs' 10 games and has been sidelined since halftime of Dallas' Nov. 4 loss to the Portland Trail Blazers.
"He's making progress, but we're going to be cautious and we're going to be smart about it," Carlisle said. "He's played hurt a lot in his career. This situation is different, though. We're early in the year. There's something that has hung around that needs to be addressed and be expunged, so we're working on it."
Mavs owner Mark Cuban echoed Carlisle's sentiments about not having Dirk come back before he's ready.
"With so many guys out, there's no reason to rush him back. If this was a playoff game, he'd be playing. But when you're missing three of your other top six or seven, that's putting too much pressure on him."
The Mavs are also without guards Devin Harris (right big toe sprain) and J.J. Barea (left calf strain) for an extended period. Dallas signed Jonathan Gibson, who was the team's final preseason cut, on Friday to address a glaring need for guard depth.