Bowling legend Allan Donald believes Steve Harmison's fear of the highest stage could have put paid to his Test career.
England take on South Africa in the first Test at Lord's on 10th July - in a clash being shown live on Sky Sports 1 - but the Durham paceman will be missing.
It is a massive fall for a player who was the Word's Number One bowler at one stage of his career but is struggling to re-capture that form.
Donald was England's bowling coach last summer when Harmison admitted being 'dead scared' to bowl against the West Indies at Old Trafford.
And the former South African bowler - who now helps Warwickshire's bowlers with his expertise - believes it will be difficult for Harmison to come back.
He told the Daily Mirror: "I've never seen a bloke as low as Steve was during that Manchester Test against West Indies.
"When he came off the field he admitted he was dead scared. He was scared of letting the ball go and he soon realised that Michael Vaughan could not turn to him.
"He had to go and dig very deep in that second innings and he did. As a result he saw a friend of his, a psychologist, who got into his ear and he bounced back and got better.
"Sometimes I feel that there is a fear of being on that massive stage. It could be.
"Does he know and fully understand how he became the world's No.1 bowler? Or did he just bowl?
"I had my doubts as to whether Harmy really understood how he had got there. That's why inconsistencies creep in."
Donald believes current South African paceman Dale Steyn will also feel pressure in the up-coming Test series similar to that Harmison experienced - and how he deals with it will be crucial.
He added: "Dale is in the same position as Harmison was and has made amazing progress to be the most talked about bloke at the moment. As a young guy he was a bit of a spray gun.
"But does he understand why he is there? When you're world No.1 you have to realise how you got there. When the pressure comes and you are searching for form, that's when you work out how you got there."