The promising full back has played for England from Under-18 to Under-20 level.
Last month, West Brom manager Slaven Bilic had called on European soccer’s governing body Uefa to do more to protect clubs against losing their best prospects after the Baggies failed to agree a new contract with Ferguson.
Palace, currently 14th with 42 points, host seventh-placed Tottenham Hotspur in their final game of the season on Sunday.