[UPDATES with official signing]

D.C. United has signed Chris Durkin, a 16-year-old midfielder-defender who captains the U.S. under-17 national team, to a homegrown contract.

Durkin underwent a medical exam and signed the multiyear deal Tuesday. He is scheduled to start Wednesday when United faces the second-tier Fort Lauderdale Strikers in the U.S. Open Cup’s fourth round at Maryland SoccerPlex.

“His maturity, ambition and understanding of the game are unparalleled for a player of his age,” General Manager Dave Kasper said. “Under the leadership of academy director Nolan Sheldon, Chris rapidly excelled in each of his five years in our academy and was integrated into first team trainings and friendlies for the past year.”

Durkin, from the Richmond suburb of Glen Allen, joined United’s academy in 2o11, the club said.

At 16 years and 4 months, Durkin is the third-youngest player to join United’s pro set-up: Freddy Adu was 14 and 7 months in 2004 and Santino Quaranta was 16 and 3 months in 2001. Bobby Convey was 16 years and 7 months when he was drafted in 2000.

United’s interest in signing him first surfaced on the Insider this spring and accelerated last week.

The holding midfielder and center back also weighed European opportunities.

Durkin will train with United throughout the summer and return to the U.S. U-17 residency program in Bradenton, Fla., full-time in August and resume playing with the youth national team in preparation for the U-17 World Cup in fall 2017. He will join United following the U-17 World Cup next year.

He is eligible for Open Cup matches only this year.

In January, he was among 32 players invited to the residency program. Last month, at a tournament in India, he captained the U.S. squad in each of the three matches he started. The Americans played five games over 11 days. In the opener, Durkin started in central defense, then shifted to midfield. Earlier this year, he played in the back against Belgium, Turkey, Brazil, England, Russia and Canada.

United has three homegrowns on the first-team roster: goalkeeper Bill Hamid, defender Jalen Robinson and midfielder Collin Martin. Hamid, the 2014 MLS goalkeeper of the year, is a senior national team prospect, while Robinson is a reserve center back and Martin has battled several injuries. Hamid (Annandale) signed with United out of high school in 2009 at age 18, while Robinson (Baltimore) and Martin (Chevy Chase) left Wake Forest University early.

Past D.C. academy signings were midfielder-defender Andy Najar (now with Belgian club Anderlecht), defender Ethan White (New York City FC), midfielder-defender Conor Shanosky (Louisville City) and forward Michael Seaton (waived by the Portland Timbers last month).

Durkin rose through the Richmond Kickers youth program and joined the Kickers’ third-division pro club as an amateur last summer.