The 20-year-old will join the Potters on January 1, 2014 when his contract with New England Revolution expires.
Scholes said: "We've played against five MLS teams in the last two years and have been consistently impressed with the quality we've come up against.
"We've already taken two players directly from the MLS in Geoff (Cameron) and Brek (Shea).
"Geoff readily adapted to life in the Premier League by making 35 league appearances for us in his first season at the Britannia Stadium.
"Brek and Maurice will be looking to do likewise this season and we're confident that Juan will be able to follow suit."
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