Rotherham manager Ronnie Moore has extended the loan of Swindon full-back Callum Kennedy until the end of the season.
The 21-year-old has so far made four appearances for the Millers since joining them on an initial month-long deal in February.
United's chief operating officer Paul Douglas told the club's official website: "We are very happy that Callum will be remaining with us until the end of the season.
"He has played very well during his short time here. He has fitted in well and he was keen to stay on."
Kennedy, a product of the Robins' youth system, spent a month at Gillingham earlier this season and featured in three games.
He signed a new one-year contract at the County Ground in January but chose to go out on loan again after finding first-team football hard to come by.