The 23-year old striker has scored just one goal in eight appearances for the Black Cats since his summer move from AZ Alkmaar but Klinsmann feels he will take time adapt to the English game after scoring at will in the Dutch Eredivisie.
"No concern at all. First of all, you never know what you'll get when you make a move like this," Klinsmann told MLSsoccer.com. "Every move to a new club is a jump in the cold water, and you start at zero again. It's just reality for everyone.
"Courageous, first of all, for making that move coming out of a comfortable nest in Alkmaar where everybody admired him to the shark tank of the Premier League. Not knowing who's going to feed me there; who are the other players; what philosophy does this coach have? Lot of question marks going in there.
"I've watched almost every game so far, and he's really performed. He hasn't scored the goals yet, but he did perform. Now going into another coach, he's in an ongoing, challenging process, which is great. He will get stronger and stronger going through that. He will gain more experience. He will look at things differently. He's learning on a daily basis.
"Eventually, his talent with his eagerness to compete and succeed will guide him through that."
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