Manchester United striker Marcus Rashford carried a back injury last season due to growing pains.
The Sun says his condition was so bad he sometimes could not travel to games on the train.
And Old Trafford boss Jose Mourinho kept Rashford's ailment a secret amid fears defenders would target him.
He was 5ft 11in when Mourinho arrived at the club last summer — but is now an inch taller.
It meant Mourinho had to leave Rashford, 19, out of some games that were going to be too physical.
In fact, he was being flown down separately to restrict the time he would be sat still on a train, which could have affected his back problem.
Now Rashford is fully fit, Mourinho plans to use him as a more regular starter.