Borussia Dortmund sporting director Michael Zorc has suggested that Jadon Sancho's off-the-field behaviour has become a problem for the German club.
The 20-year-old has again been in excellent form for BVB on the field this season, scoring 20 times and contributing 20 assists in 40 appearances in all competitions.
The England international has had his disciplinary problems during the 2019-20 campaign, though, and was fined and left out by his club when he returned late from international duty last October.
Sancho's timekeeping has also been an issue this term, while the youngster was recently fined by the DFL for breaking lockdown rules by having a haircut inside his own home.
Amid claims that Manchester United are keen to secure a summer deal, Zorc has suggested that the German outfit are becoming frustrated with the former Manchester City youngster.
"Jadon is not only an exceptional footballer who is noticeable on the pitch but now and then also outside of the pitch," Zorc told Bild "Sometimes it's not easy for us."
Dortmund are believed to value Sancho at £115m, but United are allegedly wary of committing to a deal of that size at this stage due to the current uncertainty in the world of football.