Oviedo will play no part at the upcoming tournament in Brazil as his recovery from a broken leg continues.
But the 24-year-old - who plays his club football for Everton in the Premier League - will travel to South America with the squad and thinks Costa Rica are capable of springing an upset or two.
"This is a very strong group," Oviedo said.
"These three games will be very hard and we need to play well, we have to be prepared for them and very focused.
"We'll need to stay concentrated because we will be playing against three of the best teams in the world. But nothing is impossible.
"I think Costa Rica has a good chance but it is difficult for everyone in the group.
"We have more experience than the last World Cups and we have so many players playing in Europe in important tournaments, which is important.
"We have good players and a good team, a solid team which is very important.
"We can cause the bigger teams a few problems, that is for sure."
Costa Rica start their World Cup campaign with a clash against Uruguay on June 14.
