This is according to 20-year-old defender Jean-Clair Todibo's interview to Bild, earlier this year.
The rule was apparently implemented to ensure that Messi doesn't get injured in training and is fit to play the maximum number of matches that he can.
"We all knew that he couldn't get injured. Messi was defended very carefully in training.
"I learned a lot from Messi and I even tackled him a few times, but I was careful not to hurt him."
Lionel Messi mending bridges with Barcelona
Lionel Messi is reportedly on a mission to prove to the powers that be at Barcelona that his allegiances to the club have not wavered, after handing in a transfer request following their dismal end to the 2019/20 season.
The Argentinian superstar publicly stated his intent to leave Barcelona, citing a clause in his contract that allowed him to walk away for free, after the club was dumped out of the Champions League by Bayern Munich.
However, La Liga and Barcelona joined forces to insist that he could not leave on a free and that any purchasing party would have to shell out the €700m release clause to prise him away.
Unwilling to drag 'the club of my [his] life' to the court over the ruling, Lionel Messi then announced that he would stay for one more year and see out his contract, despite missing training in an attempt to showcase his intention to leave.
"I wasn't happy and I wanted to leave. I have not been allowed this in any way and I will stay at the club so as not to get into a legal dispute.
"There was another way and it was to go to trial. I would never go to court against Barca because it is the club that I love, which gave me everything since I arrived. It is the club of my life, I have made my life here."
The player has since returned to Barcelona training as he aims to get match fit before the club kicks off its La Liga campaign against Villarreal on September 27.Published 14 Sep 2020, 13:14 IST