Sebastian Kehl says Shinji Kagawa would be welcomed back to Borussia Dortmund with open arms.
Douglas has described his arrival at Barcelona as the pinnacle of his career ahead of their visit to Villarreal on Sunday.
Liverpool striker Adam Morgan has joined Yeovil - initially on loan, with the move to be made permanent in January.
The 19-year-old England Under-20 international, who has made three appearances for the Reds, will sign permanently when the next transfer window opens on January 1.
"Adam has been generating a lot of interest recently, he had a lot of options but he has chosen to come to us," manager Gary Johnson told the club's official website.
"We are taking him on a deal until January and then he will join us on a permanent contract after that.
"Adam is a great prospect, I personally feel he is ready to play Championship football now.
"I remember Robbie Fowler saying that Adam is one of the best finishers he has seen in a long time. That is big praise."
Morgan's addition comes at the end of a busy day for the Glovers with Nottingham Forest striker Ishmael Miller and Everton midfielder John Lundstram also joining on loan.