"There will definitely be some changes. If not from the start, then they will be made during the game itself", the head coach said.
Portugal are using the two friendly matches this week to prepare for the 2018 FIFA World Cup.
With former champions Spain, Morocco and Iran joining them in Group B, the Portuguese will fancy their chances of qualifying for the Round of 16.
Their opponents on Tuesday, the Netherlands, have endured a torrid last few years, particularly considering their illustrious footballing history and tradition.
The Dutch have failed to qualify for back-to-back major tournaments for the first time since 1980.
Ronald Koeman has been hired in an attempt to turn the tide for the Euro 2020 qualification campaign, which kicks off in September.
He began his reign with a 0-1 home defeat to England on Friday, and will be hoping his charges turn in a positive performance against the odds when they face the European champions and the world player of the year in Ronaldo, who has scored 19 goals in his last nine games for club and country.
"He is one of those players that can always score. Even when the team is playing badly, they have the ability to score out of nothing", Koeman told reporters on Sunday.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)
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