"At the moment, Danny goes to the U21 Championship with England and will then return to our squad," Villas-Boas said.
"He has had a great season in Sunderland. We are aware of it. He's a player we have to consider.
"There are decisions to be made at this club in the summer. We have to look to build, but we are also aware that we have to hold on to good players to improve as a club."