Grêmio fullback Vanderson has sent a letter of apology to Brentford after his transfer to the club did not materialize.
The recently promoted Premier League club were hoping to secure the 20-year-old's signature in the January or summer transfer window.
However, he has chosen to sign for Monaco instead.
According to UOL in Brazil, the player went as far as to write a formal apology to Brentford for rejecting the club.
Vanderson is said to have reached a verbal agreement with Brentford, before turning his back on the English club for Monaco.