Adam Matthews arrives in Sunderland as something of an unknown quantity. Dick Advocaat's first signing (alongside last season's Liverpool loanee, Sebastian Coates) arrives from Celtic with considerable experience for a 23 year old, yet finds himself untested in the cutthroat world of the Premier League. The right back will look to compete with Billy Jones for a place in the starting lineup, but is also capable of switching to the left hand side in a pinch, much like Phil Bardsley. Unlike Bardsley, however, he doesn't seem to possess quite the same goalscoring threat, notching just four in 101 league appearances for Glasgow's green and white. Sunderland fans won't mind a scarcity of goals however, as long as he can provide some defensive stability to a club seemingly embroiled in a permanent relegation battle. Although born in 1992, he is already nearing 150 league appearances in professional football, having spent two seasons at Cardiff and four years north of the border. Despite this, the Welshman will be considered an unproven commodity come the first game of the upcoming season. He has yet to play in the top flight of English football, and will undoubtedly come under considerable scrutiny from the Stadium of Light faithful. In order to ease a few fears regarding Matthews' ability, here are eight facts every Sunderland fan should know about the promising young right back. Hopefully he can live up to his potential and make a positive impression on Wearside.