Striker Romelu Lukaku, who returned to Chelsea for a club record £97.5m in August, was "not happy" with his bit-part role under Blues boss Thomas Tuchel earlier this season.
The 28-year-old also told Sky Sport Italia - in an interview recorded several weeks ago but aired on Thursday - that he wanted to go back to Inter Milan in the near future.
"I'm not happy with the situation, this is normal," said Lukaku at the time. "But I am a worker and I must not give up."
The Belgian has scored seven goals in 18 club appearances since he re-joined Chelsea this summer. He has also been hampered by injury and illness and, at times, found himself left out of the starting line-up when fit.
However, Lukaku has had a recent upturn in form, scoring in his last two Premier League appearances, after discussions about his role with Tuchel.
"I think I needed a performance like this today. The manager has his reasons but I kept working hard," Lukaku said after scoring in the 3-1 win over Aston Villa on 26 December.
"It's a good win and personally for me I'm happy. Balls from crosses and the movement in the box - I try to be less static."
Lukaku first signed for Chelsea in 2011 as an 18-year-old from Anderlecht, but struggled to break into the first team at Stamford Bridge, eventually leaving for successful stints at West Brom and Everton and a less convincing two-season spell at Manchester United.
His move to Inter Milan in August 2019 was a huge success, however, as he scored 64 goals in 95 appearances and helped the Nerazzurri end an 11-year wait for a Serie A title.
"I want to say a big apology to the Inter fans because I think the way I left should have been different," he added in his Sky Sport Italia interview.
"I really hope in the depths of my heart to return to Inter, not at the end of my career, but at a still good level to hopefully win more."