Top 15 youngest players in MLS history

1. Freddy Adu — 14 Years, 10 Months, 1 Day

Freddy Adu was just 14 when he made his MLS debut for D.C. United. Adu came on as a substitute in the 61st minute in his side's 2-1 win against the Colorado Rapid. He would go on to play 96 times for D.C. scoring 11 times and making eight assists. He also won MLS Cup with the Black-and-Red in 2004 -- the year of his debut.

However, Adu did not live up to the hype that was built around him. He joined Real Salt Lake after D.C. before going to Europe with Benfica. He could not establish himself in the Portugese side, so was sent on loan to multiple clubs including AS Monaco, Beleneses, Aris and Caykur Rizespor.

Adu returned to MLS with the Philadelphia Union but then became a journeyman again with spells at Bahia, Jagodina, Kuopion Palloseura, Kuopio Futis-98, Tampa Bay Rowdies, Las Vegas Lights and Osterlen -- which was to be his final club.

2. Julian Hall — 15 Years, 6 Months, 7 Days

Julian Hall made his debut for the New York Red Bulls last year in his side's 1-0 loss to the Chicago Fire. Hall came on in the 81st minute but that was to be his only appearance of the campaign. He has featured since as a substitute this season in RBNY's 4-0 win over Inter Miami.

He has represented the United States at U15 level -- where he has scored four times in nine games. The left-winger is also eligible to play for Poland.

3. Alphonso Davies — 15 Years, 8 Months, 15 Days

Alphonso Davies came on as as substitute for the Vancouvar Whitecaps in their 2-2 draw with Orlando City when he was just 15. He was used as a winger for the Canadian side and went on to score eight times in 64 MLS games.

He would then join Bayern Munich where he was converted to a left-back. He has had great success with the German side, winning the Champions League and the Bundesliga five times. The Canadian's time at Bayern could be coming to an end with Davies being linked with a move to Real Madrid.