The time and date of the event - 19:00 on April 19 - were chosen to commemorate Petrov's shirt number at his English Premier League club Aston Villa, with the fans being asked to wear shirts with number 19 on their backs.
Current and former players, coaches and top officials are expected to attend the 19-minute event which will be broadcast live on several TV channels.
"I know everyone thinks the same, but I'll write it here anyway...You'll Never Walk Alone," Manchester United striker and Bulgaria's all-time leading scorer Dimitar Berbatov wrote on his Facebook page on Thursday.
The Bulgarian Football Union (BFU) is dedicating this week's round of the domestic championship, played between Tuesday and Thursday, to Petrov with players wearing specially signed shirts in support of him.
Several league matches have been stopped in the 19th minute, with the crowd applauding for a minute.
Petrov, 32, who is Bulgaria's most capped player with 105 international appearances, has started treatment at a London hospital.
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