Friendlies are sometimes taken lightly by some countries while other countries take the match seriously. I see the line for Greece has gone from 4.20 to 3.00 while the line for Portugal has gone from 1.75 to 2.10. Perhaps the betting public thinks Greece will take the match more seriously.
Greece has typically not done well at friendlies. However, they will be sporting a full squad in this one. Portugal will be without Ronaldo, Nani and Deco and their starting goalkeeper is questionable for this one.