Mainoo has made four consecutive Premier League starts for the first time in the 2025-26 campaign since interim manager Michael Carrick took charge.
Carrick has won his opening 4 games alongside Mainoo who United fans have missed since he was forced out the side under Amorim who also refused to let him leave to Napoli over the summer.
Mainoo is pressing to be included in Thomas Tuchel's England squad ahead of the World Cup in a scenario that doesn’t look impossible for the 20-year-old.
Lineker, speaking on The Rest is Football, joked that the young midfielder should sue Amorim after nearly destroying his career.
"Do you know what? If I was Kobbie Mainoo – and I say this in jest – I'd be thinking about whether I should sue him (Amorim) or not," he quipped.
"He's taken a year out of that kid's career. This kid is a wonderful footballer.
"God, he makes it look so easy. He wants the ball, he receives it with anyone around him and he turns, always makes the right decisions, he's graceful.
"I mean, come on! He's been absolutely detrimental to his career."
Mainoo has made 18 appearances across all competitions in the 2025-26 campaign and has 3 assists to his name. He is only growing better under Carrick who will scratching his head as to why Amorim refused to give him a chance in the side.