Real Salt Lake Academy forward Axel Kei made history Friday night, becoming the youngest-ever player to make a professional appearance in American team sports.

Kei, a second-half substitute for Real Monarchs (RSL’s USL Championship affiliate), was 13 years, 9 months and 9 days old upon entering a second-division match against Colorado Springs Switchbacks FC.

Kei joined the 0-0 draw in the 61st minute, replacing former US men’s national team striker Bobby Wood, who’s more than double his age. He had a late chance at a game-winner, though a Colorado Springs defender intervened on an 85th-minute cross from Milan Iloski.

At last summer’s inaugural MLS NEXT Cup Playoffs, Kei helped RSL win the U-15 national title with a 2-0 victory over the Philadelphia Union. He took home the Golden Boot, memorably netting a hat trick (seen below) and tallying five goals total.

Axel Kei scores a hat trick for RSL Academy | MLS NEXT Cup 2021

RSL historically have one of the strongest academies in MLS, with first-team regulars like goalkeeper David Ochoa, center back Justen Glad and right back Aaron Herrera all coming through their youth development system.

As Kei works toward a homegrown deal and accumulates professional minutes, he could become among the youngest-ever players to sign an MLS contract. The current leader is Freddy Adu, who joined D.C. United in 2004 at 14 years and 168 days of age. Kei's also been in US youth national team camps and was born in the Ivory Coast before moving to Brazil.

Real Monarchs debuted in 2015 and won the USL Championship title in 2019. Meanwhile, RSL won MLS Cup in 2009 and advanced to the Concacaf Champions League final in 2011.

Starting in 2022, MLS plans to launch a new professional league that’s designed to accelerate the development of elite talent by providing a highly competitive environment for rising stars to compete alongside established professional players. Concurrently, MLS NEXT is in its second year of competition.