Santos and Calero are two of the Rams’ brighter up-and-coming stars and McClaren thinks that, with a full pre-seson behind them, they will be ready to make the step-up in 2015/16.
McClaren was actually hoping that Santos and Calero could have played a bigger role this term, but believes that next season will now be their breakthrough one.
"Alefe Santos and Ivan Calero, I said at the beginning of this season that they should be pushing to break into the first-team before the end of the season," he said.
"It has not been the case, but next season we fully expect them to start coming through and challenging for the first team. Pre-season is big for them."
Derby have a good recent history of developing their own youngsters and McClaren has already shown his faith in the academy system.
The 53-year-old boss has given the likes of Will Hughes, Jamie Hanson and Mason Bennett first-team opportunities this year and Santos and Calero will be hoping that they can get more regular football next term.
Santos is an exciting winger, with an abundance of tricks, while Calero is a creative central midfielder who excels on the ball.
The pair have both stood out for Derby's under-21 side this term and the hope is that they will burst onto the senior scene next year, when McClaren feels they will be better prepared for the step up in class.