Tickets for a much anticipated soccer exhibition match to be played between Celtic Football Club of the Scottish Premier League and Sporting Clube de Portugal from the Portuguese Liga are not selling well, according to stadium sources.

Despite growing worldwide interest in soccer after the World Cup, over one third of the stadium remains empty, say booking office staff.

The match is to be played in Fenway Park, the Boston Red Sox homeground next Wednesday, July 21.

So far, 25,000 seats have been sold of the 37,400 available, according to Sam Kennedy, the Red Sox chief operating officer, who expressed surprise at the slow rate of ticket sales after soccer seemed to have finally caught on in America after the World Cup.

“We anticipated that it would be a highly sought-after event given the novelty of soccer at Fenway, but we knew it was not going to be like a Springsteen concert or a Red Sox-Yankees game. But based on the pace of sales and what we anticipate from a walk-up crowd on game day, we have very good chance at a sellout, but it’s not guaranteed,” he told the Boston Herald

Most of the lower-priced seats from $20-$50 have sold out. But seats in the Celtic Football section are listed on Ticketmaster for $75 and $100, the neutral section has seats available for $80 and $100 while bleacher seats for the Portuguese team are plentiful at $40 and $50.

Andrew Zimbalist, a sports economist at Smith College, said that the game was being hosted to try diversify the sporting events being held at the stadium which is currently being used just 90 days a year: “It’s a great park, people love it, so they’re trying alternative sports and other uses of it,” he said. “Even if they don’t sell out, it’s still an effort worth doing, because in the long run it will be productive for them.”