Fernando Torres has arrived in Italy ahead of his proposed loan move from Chelsea to AC Milan.
Sebastian Kehl says Shinji Kagawa would be welcomed back to Borussia Dortmund with open arms.
The 18-year-old has put pen to paper a one-year deal, with the option of a further 12 months.
Preston has been with the Blues academy for over five years.
He had a loan spell at Skrill North side Worcester City last season where he made two first-team appearances for the Dragons.