Argentine Jorge Lopez was killed in a suspicious road accident while in Sao Paulo in July.
Guardiola was sporting the top – which read ‘#JusticiaParaTopo’ – during his pre-match press conference before Bayern Munich emphatically dumped Porto out of the Champions League. The message appeared to support a campaign to investigate Lopez’s death.
Lopez was killed when a taxi he was traveling back to his hotel in was hit by a stolen car being chased by police.
UEFA revealed that the Spanish manager had been disciplined because of an ‘incident of a non-sporting nature’, in a move likely to cause public outcry.
The European governing body’s disciplinary regulations read: ‘A breach of these principles is committed by anyone who uses sporting events for manifestations of a non-sporting nature.’ They are to review the case on May 21.
On wearing the shirt, Guardiola said: ‘Last week, the family has given me the T-shirt. I woke up this morning and knew that I would put it.’
Lopez was a highly regarded journalist in South America and his passing drew huge outpouring from the very top of the game.
Last year Atletico Madrid boss and former Argentina midfielder Diego Simeone tweeted that Lopez was ‘not only a great journalist’ but ‘also a friend’ after hearing of the news.
Lionel Messi also dedicated Argentina’s World Cup semi-final win to the 38-year-old.
‘Big hug to all the Argentina fans and a very special memory for Jorge “Topo” Lopez,’ wrote Messi after their penalties victory against Germany.
‘This victory is especially for you, my friend. A big hug to the family, lots of strength.’
Earlier this month Javier Mascherano devoted the launch of his new book to Lopez, while he and Messi were both pictured holding placards with the message on late last year.
So too did legend Diego Maradona. Both Barcelona and Atletico Madrid have posed in front of a board during team photographs.
FIFA also paid tribute to the journalist, with head of media Delia Fischer saying they ‘would like to send our sincerest condolences to the family, colleagues and friends of Argentine journalist, Jorge Lopez’.