The midfielder is backing Saints to become a top-flight force.
"The club is only going to go onwards and upwards," the 25-year-old, who last week agreed a two-year deal with League One side Preston, told the Daily Echo.
"There's a passion behind the scenes that means they won't stop until they achieve what they want.
"There is going to be a time where Southampton will be a force to be reckoned with in English football.
"In the next five years, I expect them to be right up there with the best of them."