By lunchtime yesterday they were closing in on a complete sell-out - only around 3000 tickets remained - for a match that will raise funds for the former Celtic player's cancer foundation and other charities.
The game may have sprung from sombre circumstances - Petrov is on the road back from acute leukaemia that is mercifully now in remission - but it has brought together a raft of people willing to pay tribute to a player who spent seven trophy-laden years at Parkhead, represented Aston Villa for a similar period, and won more than 100 caps for Bulgaria.
Charity games have a habit of attracting figures from the world of showbusiness, enlisted to help encourage non-football fans to come along - this weekend's star attraction is Louis Tomlinson from One Direction, said to be a beat combo popular with the young folks - but the majority of the assembled squads, representing a Celtic XI and a Petrov XI, are those who played with or knew Petrov during his playing days. Most intriguing are the two names at the end of the list.
Unlike most of the others, the connection between Petrov and John Terry is not immediately obvious but the Bulgarian soon reveals details of a friendship that has blossomed over the years. The Chelsea captain's public persona does not suggest he is someone wih a particularly strong charitable streak but Petrov was keen to emphasise how much he appreciated Terry's involvement in his big day.
"Every year in the Premier League there's a meeting with the club captains to talk about things with referees and all that," explained Petrov. "So I've known John from that. He's been really good with this event and been the main man, getting everybody together and organising things.
"He's been a great support to me throughout my treatment. When I called him and asked him to play he said he'd be there and just to let him know when it was. He said that every player would love to play at Celtic Park in front of that crowd.
"John didn't come and see me when I was having my treatment but he called and texted me a lot to see how I was doing. I wasn't the best at getting back to people. They'd send me a message and I'd get back to them about a month later. I was drained and there was a lot going on so I wasn't that great at replying. Most of the boys were good with it as they knew I couldn't talk most of the time as I was in the hospital."
Terry won't be the only pantomime villain appearing on the day, however. Joining him in the Petrov XI will be Carlos Cuellar, the former Rangers defender whose previous appearance at Celtic Park ended with him being sent off for stopping a Shunsuke Nakamara shot with his arm. The Spaniard, now at Sunderland, became good friends with Petrov during their time together at Villa and the Bulgarian revealed the prospect of being heckled hadn't put Cuellar off from signing up to lend his support.
"I spoke with him and asked him to play as we're very close," said Petrov. "He said 'no problem' as it's such a great cause and for causes like this you don't separate colours. I told him he might get booed a bit and he said, 'that's fine, I'll boo them back!'. So he's very good about it all. He's excited about it and, as he's not playing at the moment, he said he's not going to be taking it easy. He's coming for a competitive match!"
Nostalgia will hang heavy in the air as well. There will be a reunion of the group that reached the UEFA Cup final a decade ago - only Alan Thompson is missing from the starting line-up from Seville - and Petrov is looking forward to catching up with them all.
"My family had a really great time in Glasgow with the people. We got such a warm welcome. On the pitch we enjoyed success and I played with such great players and characters. There are so many things that make me laugh. The other day I saw Chris Sutton commentating on the Celtic game wearing the same shoes he had on 12 years ago.
"We had some big, big characters here and good fun. We knew when there was business to be done everyone had to be up for it. You didn't want to mess up in the dressing room and on the training pitch with those guys. Every single one has been great to me throughout my career."
Petrov, who hopes to play for both sides for short spells of the game, has held it together remarkably well even during the darkest days of his illness and hoped this weekend's event won't belatedly drive him to tears. "It's emotional knowing how many people will be there. I've been asked how I'm going to react and I don't really want to think about that. I hope I don't cry. I haven't cried all through these hard times so if I start crying I might not stop. So I'd better not start."