Danijel Subotic has become Portsmouth's first signing of the transfer window.
Pompey have paid an undisclosed compensation fee to Swiss side Basel for the services of the striker, who joins on a three-and-a-half year contract.
The highly-rated 18-year-old impressed during a recent trial at Fratton Park and Harry Redknapp believes he has a bright future ahead of him.
"He was recommended to us so we brought him over for a few days' training and he did well," Redknapp told the club's official website.
"We've taken a gamble on him and hopefully he's one for the future.
"We'll just have to see how he goes."
Portsmouth have lost John Utaka, Kanu, Sulley Muntari and Papa Bouba Diop to the African Nations Cup and Redknapp plans to do more business over the coming weeks.
"We need to get some people in but it's hard," he said.
"You look around and who is going to loan you anybody? The only place you might find a few is abroad.
"We need to strengthen out wide and up front in particular."