Concerns have been raised about one of the pitches Pompey will play on in pre-season.
Fears have been aired over the playing surface the Blues will use when they meet FC Edmonton on July 21.
They take on the Canadian outfit at their Commonwealth Stadium as part of the three matches they play in Canada and USA this summer.
There has been some reservations about the FieldTurf technology used to make the artificial pitch there. The synthetic material is used at sporting arenas across the world, especially american football, and is approved by world governing body Fifa.
The likes of Chelsea, Newcastle, Aston Villa, Arsenal and Birmingham also use the surface at their training ground.
But some clubs have reservations about putting their players through their paces on it.
Edmonton are shelling out 800,000 to put on three games featuring Pompey, Brazilian side Vitoria and Chile's Colo-Colo.
But both Manchester City and Celtic turned down the chance to meet them before the Blues came to an agreement.
Edmonton spokesman Mel Kowalchuk admitted the FieldTurf has been a problem in attracting teams.
Kowalchuk said: 'We lost Celtic and Man City because of the turf.
'We lost Celtic the day after they announced they were putting artificial turf into Commonwealth Stadium.
'They had already agreed to a game in Seattle on FieldTurf and said they were only willing to play one game on it.
'Man City sounded excited to come to Edmonton until they found out it wasn't grass any longer.
'They said to try them again next year. There's still a lot of people in this sport, especially with the top teams, who are very much old school, no matter what Fifa approves.'
Pompey start their tour when they face Mexican side Club America in San Diego on July 14. They then meet Edmonton on July 21 before taking on DC United in Washington on July 24.