Williams was added to the lineup for Friday's game against the Mets, Christina De Nicola of MLB.com reports.
The 25-year-old didn't start in any of the last three games, but he'll take over at third base and bat ninth after Miguel Rojas (foot) was scratched from Friday's lineup. Over 18 games since joining the Marlins, Williams has hit .200 with a double, six runs, an RBI and three stolen bases.