Denmark head coach Age Hareide admits the “mixed up” nature of Scotland’s personnel means it is hard to know everything about them.
Strachan named two separate squads for Thursday’s 1-0 win over Czech Republic and Tuesday’s match at Hampden Park and will make changes against the Danes.
“We saw the game against Czech Republic and they did well to win,” former Malmo boss Hareide told BBC Scotland.
“But I know some of those players are not playing now.”
But Hareide, who tasted victory over Scotland as Norway boss and with Malmo over Celtic, pointed out that he knows the Scottish style and has great respect for Scotland coach Gordon Strachan.
“I know a lot, but it’s mixed up, so you don’t have complete control over what we do,” said the Denmark coach.
“They always have a heart to play football and that is why we wanted to play against Scotland.
“We know we will get a fight – even as a friendly. It’s a real football country.
“Gordon Strachan’s been around for a while and has great experience.”
Hareide took charge of Denmark in December, succeeding Morten Olsen, who had been in charge for 15 years.
Tottenham Hotspur midfielder Christian Eriksen explained that the team are still adjusting to the new approach.
“At the moment, it’s about winning games and getting used to the new system and style of playing, so hopefully it’s going to be a good game,” he said.
“We are really eager and we want to learn the methods of how we are going to play in the future.”
Denmark come into Tuesday’s contest having won a friendly last week, with the Danes defeating Iceland 2-1 at home while Scotland were defeating the Czechs in Prague.
“We are both going to be sitting on the couch this summer,” added Eriksen, whose side have not won away from home in their last five outings.
“Scotland have a lot of confidence going into this game and so do we.
“We always want to create goals – it doesn’t matter where we play.
“Of course our away record is not very good, but every day is new and hopefully tomorrow will be a good one.”