Southampton manager Ronald Koeman believes that Memphis Depay may require some time to adapt to the demands of English football.
The 21-year-old has agreed to join Manchester United at the end of the season in a deal worth around £22m, subject to a medical.
Depay has been a shining light for current club PSV Eindhoven, scoring 49 goals in 122 appearances for the Eredivisie side, and Koeman expects his fellow Dutchman to shine at Old Trafford in the long term.
"For him it's a fantastic move," he told reporters. "He has had a great season and last season made the step up to be a senior player, not a junior player.
"He still has to develop himself. It will be tough for him because the Premier League is tough in a physical and mental way. It's a big step for him. But he's a great talent, a fast player and a very good signing for Manchester United."
Depay was also linked with moves to Paris Saint-Germain and Liverpool, before opting to join United.