The Rapids sent goalkeeper Clint Irwin, midfielder Dillon Serna and defender Chris Klute to Everton, while defender Shane O'Neill trained at Fulham, in order to gain experience working in an ultra-professional environment.
"This is a great opportunity for our guys to get some extra training in during our offseason," said Rapids technical director Paul Bravo.
"We all know Everton to be an excellent club, one that is fun to watch and enjoying an excellent run of form right now. It will be great for these young players to see how Everton trains and prepares, and for them to experience the culture in England."
Irwin, Serna and Klute returned from Goodison Park on the weekend while O'Neill's stint with Fulham should conclude early this week.
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