Williams will cover for injured skipper Callum Davidson at Preston.
Manager Darren Ferguson said: “He gives us that balance we’ve been looking for down the left-hand side as he is naturally left footed.”
He added: “We have been playing right-footed players on the left-hand side and whilst the people who have been doing the job have done okay, Tom can give us that extra balance.
“He knows the league, has good experience, he is quick and has good size. He is with us on loan and we will see how it goes.”