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.
Arsene Wenger remains confident Arsenal captain Robin van Persie will not be sold this summer.
The Holland skipper was relaxed about his future as he collected the Football Writers' Association Footballer of the Year award last night, insisting no matter what happens during the rest of his career he would "always be a Gunner".
Van Persie, 28, is set to sit down with Arsenal at the end of the season for discussions over a contract extension, with another year left on his current deal.
Despite suggestions the Gunners would look to cash in on their captain - as they did earlier this season with contract rebel Samir Nasri who eventually was sold to Manchester City for £24million - Wenger maintained that scenario was not on the horizon.
"Who would want to lose his best player? My desire and my wish is to find an agreement with Robin van Persie, extend the contract and stay with us for a longer time. Hopefully we can reach that," said Wenger, whose side host Norwich tomorrow aiming to strengthen their grip on third place in the Barclays Premier League.
"If that wouldn't happen, we will still want him to stay, but I am more focused on the first situation.
"I think what is important for us is that we find an agreement with him to be happy and to stay and finish his career here."
Wenger continued: "I cannot guarantee that it will go well, but I am quite confident.
"I believe Robin is committed to the club, I feel that the club has shown great commitment to him over the years and put great faith in him.
"I brought him here a long, long time ago and he has developed fantastically well as a man and as a player.
"Today he is a world-class player and he deserves great credit. Hopefully we can keep him here."
Arsenal's hand would be strengthened significantly were they able to offer guaranteed Champions League football again next season.
That the Gunners have that within their own grasp heading into the final two matches of what started out as a testing campaign is remarkable in itself.
While Newcastle and Tottenham are both now only one point behind following their midweek wins, Wenger knows Arsenal's destiny remains in their own control.
"Our dream was to be in the situation we are in now three months ago. It is now down to us to get over the line," said Wenger, who will take charge of his 900th game tomorrow.
"That looks quite difficult at the moment because we had a few opportunities we didn't take and so we have another opportunity tomorrow which we want to take.
"The team is focused and ready to do the job, it's now for us to get over the line."
Wenger continued: "It is still open, but the advantage we have on the other teams is that we have our destiny in our own hands because we are one point ahead.
"We are in the driving seat, it depends only on our results and that is what you want when you are a top-level professional football player or at a top-level club - you don't want to depend on the results of others."
Many expected Norwich to struggle on their return to the top flight, but Paul Lambert's men head into their final two matches already safe from the relegation dogfight.
The Canaries may have been beaten 3-0 at home by Liverpool in their last outing, which was a third straight defeat, but Wenger warned against complacency.
"I expect them to play at their best because it would be absolutely non-intelligent from us to expect a team to play a little bit softer. That would not be very professional," the Arsenal boss said.
"Norwich came into this league with relatively unknown players, but what is fantastic in this job is that it is not about names, it is about performances. They have done remarkably well."