Until last week, the Gambian-born forward was having a productive rookie season in Major League Soccer, flying mostly under the radar outside of Vancouver.
But everything changed thanks to a stunning hat trick in a 4-1 road victory over the Seattle Sounders on Oct. 9 that saw the Whitecaps keep their playoff hopes alive.
"Hopefully, if he keeps the right attitude, he'll be somewhere else," DeMerit said Thursday when asked where he saw Manneh's career in a few years. "That's not a bad thing. You draft kids to mentor them and make them better and you try not to hold those kinds of guys back.
"Everyone speaks of his talent, and he knows of his talent. Now it's just about making the most of that talent."
But the 33-year-old Vancouver captain cautioned: "He's not going to go anywhere unless he performs here first."
And perform he did against the Sounders in a game the Whitecaps badly needed.
Manneh scored in the 12th, 42nd and 54th minute for the franchise's first MLS hat trick to send Vancouver to its first-ever league victory in Seattle.
"It's always great to score a goal (and) especially a hat trick. I'm really grateful to my team for the support they gave me," said the five-foot-nine Manneh, now also the youngest player to score an MLS hat trick. "It was a great feeling."
Vancouver head coach Martin Rennie has had difficulty finding a consistent strike partner for Brazilian forward Camilo Sanvezzo this season, but seems to have something with Manneh.
"Throughout the season he's just been developing as a player who's got exciting technique, great skills," said Rennie. "He's naturally just a very gifted player and now he's learning the things we've been talking about. He's learning his position a little bit more. He's learning what it means to be a professional player."
Named MLS player of the week for his performance against the Sounders, Manneh was born in Madiba Kunda, Gambia, and played soccer non-stop as a child.
"(Soccer) is all we do," he said with a smile. "That's the sport you want to play.
"We still have the field that I played on — a dirt field."
After his mother died when he was 10 years old, Manneh found his way to a Gambian soccer academy, which had a partnership with youth clubs in the United States.
Manneh left Africa at age 15, eventually finding his way to a team in Austin, Texas, where he billeted with a family that would eventually adopt him.
Fast-forward three years, the Whitecaps took Manneh with the fourth pick in the 2013 MLS SuperDraft. The club has tried to bring him on slowly, but he showed flashes of brilliance early in his professional career.
"Coming in the first year I just wanted to learn as much as I could from the coaches and the senior players," he said. "I just came in every single day, worked hard and it paid off."
Manneh came on as a second-half substitute with Vancouver trailing 2-0 against FC Dallas on April 27 and brought his team back to level with a goal and an assist.
The Whitecaps (12-11-9) are three points out of the final post-season spot in the Western Conference, but play their final two games of the season against the fifth-place Colorado Rapids (13-10-9), who currently hold down the last playoff berth.
Colorado hosts Vancouver on Saturday, before playing at B.C. Place Stadium on Oct. 27.
With five goals and two assists in 18 games, including four starts, Manneh is trying to help the Whitecaps secure a playoff berth that seemed unlikely just a few weeks ago.
"Over the course of the year, he's improved," said Rennie. "Hopefully over the course of a couple years he can improve the same or more and then you've got really a potentially consistent top player."