Ghana target Callum Hudson-Odoi says he was frustrated at Chelsea which prompted the decision to the leave the club in the recent summer transfer window.
The 21-year-old joined Bayer Leverkusen in order to get game-time under his belt after falling out of favour under Thomas Tuchel at Stamford Bridge.
The move was sanctioned by owner Todd Boehly in the summer with both parties agreeing that first team football was necessary in order to help him reach his full-potential.
"There were a lot of times when things were very good and you enjoy every part of it," he told BBC Sport Africa. "And there were times and you think, 'what have I done wrong? Or what am I doing wrong not to be playing?'
"Sometimes it was difficult and frustrating. You are sitting on the bench or might not even be in the squad and then you're like 'what on earth have I done to deserve that?'
He added, "I train well every day, I give my all in every game, but then I don't get picked.'
"Of course if there are other players doing well in your position, they should get picked as well, but at the same time, you always want to fight for your position and have a fair chance."
Hudson-Odoi has made 10 appearance for Bayer Leverkusen across all competitions and provided one assist so far.
His Chelsea contract will expire in the summer of 2024, only a year after the Leverkusen loan ends.