The pair were also in action for Spurs in their 2-1 Champions League loss to Monaco on Wednesday.
"Dier and Dembele only feel cramps in the hamstring, it's not that big an issue," Pochettino said.
"When you're in different competitions, Champions League is a different competition, we spent a lot of energy on Wednesday, it's different to the Europa League. It's new for us so it's important to learn.
"All of them are internationals, they come after a difficult summer, after playing in the Euros. It's difficult with holidays and pre-season and it's difficult to get fit."