Celtic manager Neil Lennon admits they might have to play pre-season friendlies against some Scottish Premiership rivals amid the difficulty of finding fixtures.
A 14-day quarantine rule for anyone entering the UK threatens to scupper Celtic's plans for playing overseas teams ahead of the SPL's proposed August 1 kick-off, and the fact that Premier League and Championship teams are finishing their seasons in late July means encounters against English sides are unlikely.
Even arranging games against lower-league teams in Scotland is mired in difficulty as the Scottish Championship season does not kick off until October 17 and the lower leagues will not begin any earlier.
When asked if they might have to take on Premiership teams to build up match sharpness, Lennon said: "Possibly. That's a bit of a headache in trying to get some game time, trying to confirm these clubs and games.
"At the minute we can't play anybody in England, and a lot of other countries, Italy, Spain, are up and going. We may look at some Dutch or French teams and get some quality friendlies but, at the minute, that's a difficult question to answer."