Hoffenheim football chief Alexander Rosen admits he cannot guarantee keeping hold of David Raum.
The young left-back is interesting Manchester United and Manchester City.
Rosen said, "Obviously we want to keep David.
"After all, it depends on the market. But we always have a specially coordinated approach to this kind of case.
"No matter what the decision is, we are in a good condition and we will have a strong squad. We have had some good players inside and out the door in our almost 15 years in the Bundesliga."