WESTERN Bulldogs defender Bailey Williams has signed a two-year contract extension, keeping him at Whitten Oval at least until the end of 2019.

South Australian Williams, 19, was taken with pick 48 in the 2015 NAB AFL Draft and played six games in his first season with the Bulldogs, racking up 14 disposals and 15 pressure acts on debut against Melbourne in round eight.

Playing mostly across half-back, he has appeared in four matches this season, averaging 17 disposals, three marks and three tackles per game.

Western Bulldogs list manager Jason McCartney said the club was pleased to retain Williams' services for a further two seasons.

"Bailey has shown some really promising signs since he came to the club in 2015," he told the club website.

"His poise and decision-making are of a high quality, and we're looking forward to watching him continue to develop into a quality player for the football club."