While point guard Williams has been out since November 20 due to a sprained left ankle, small forward Pierce fractured the third metacarpal bone in his right hand late last month.
"It's always good to get those guys back at practice," ESPN quotes Kidd as saying.
"I thought they looked good. It excites myself but also excites the team because we've been shorthanded."
Both Williams and Pierce returned to full practice on Monday.