Real Madrid right-back Dani Carvajal has hit out at Jose Mourinho for being "opportunistic" in failing to give young players a chance.
The Portuguese coach, who was recently appointed as Manchester United manager, sold Carvajal in 2012 to Bayer Leverkusen during his spell in charge of Real Madrid.
The 24-year-old spent one year in the Bundesliga before returning to the Bernabeu after the club used a buyback clause.
Mourinho has been criticised before for allowing young talent, including Romelu Lukaku and Kevin De Bruyne, to leave Chelsea, and now Carvajal has slammed his former boss.
"Mourinho was a bit opportunistic," Carvajal told Marca. "When I returned he'd say that I'd needed that year away, and if I hadn't done well then he'd have said that I wasn't good enough to play for Madrid.
"If it happened, I was good. If it hadn't happened, I was bad. I think I was already perfectly ready for the first team."
Mourinho has signed a three-year contract with United.