Marcus is a speedy, tricky forward who can play out wide or through the middle both as a number 10 or striker. He has been earmarked for a big future by the club and travelled to the AEGON Future Cup in 2012 with the Manchester United Under-17 team despite being an Under-14 at the time. As an Under-16, he broke into the Manchester United Under-18 side in the 2013/14 season and made 17 appearances scoring 4 goals.
In the 2014/15 season, Marcus played almost exclusively as a centre forward due to injuries and the squad size. He finished the season with 13 goals. He made his Under-21 debut in September 2015 and was included as an unused substitute for the first team away to Watford in November 2015.