Sydney youngster Brandon jack has signed a two-year contract extension, tying him to the club until the end of the 2017 season.

Jack enjoyed his best season yet at AFL level, playing 10 games in 2015.

“Brandon played a fair bit of football for us in the back half of the season and he brings some real speed into our side," Sydney coach John Longmire said.

“He is a guy that works really hard at his game, is always at the club and leaves no stone unturned in terms of the way he prepares.

“I am sure whatever happens next year Brandon Jack will give himself every opportunity because that is the sort of kid that he is.”