The younger brother of Giles Barnes, who played for WBA, Derby County and Doncaster Rovers as well as international football for Jamaica, Marcus Barnes only managed a few minutes of competitive football for Southampton. That came in the 2018-19 season in the form of a substitute appearance, playing up front at Pride Park in a drawn cup-tie.

This cameo had followed nine games on loan at Yeovil where he had scored on his debut (another FA Cup-tie v Bradford City). Entering the final year of his contract in the summer of 2019 he was loaned out to Eastleigh, in the 5th-tier of English football, but an injury in the January saw him return to St Mary’s and when the season was disrupted owing to the Covid-19 pandemic, he lost any chance to impress enough to be offered further terms and he was freed in June 2020.