Source: Team_Talk
Mattock completes Baggies switch
The England Under-21 international has put pen to paper on a three-year contract, with the option of an additional 12 months, after passing a medical at the Hawthorns.
Mattock, 19, clocked up over 50 league starts for the Walkers Stadium side despite his tender age and can operate at left-back or on the left of midfield.
Baggies boss Roberto Di Matteo has made Mattock his fourth permanent signing of the summer following the arrivals of Simon Cox, Youssouf Mulumbu and Reuben Reid.
Di Matteo told his club's official website: "Joe is exactly the kind of player we're looking for.
"He's a young, talented, English left-back who has got plenty of Championship experience despite his young years.
"Joe is hungry for success and he was very keen to join us.
"He's a quick, solid defender with a very good left foot."
