The former Arsenal attacking midfielder has also suggested that Son should start ahead of 22-year-old England international midfielder Dele Alli for Tottenham in their Premier League match against Liverpool at the Wembley Stadium in London on Saturday afternoon.
Merson wrote in The Daily Star: “They need Heung-Min Son back. He’s a massive unsung hero. I would start him ahead of Dele Alli right now.
“He gives them a lot of energy, gets in behind, makes great runs off the ball and can score a goal.”
Son is a very good footballer and is one of the best attacking players in the Premier League.
The South Korea international, who can operate as a winger or as a forward, has been away on international duty with South Korea for the 2018 Asian Games and has played just 10 minutes of Premier League football so far this season, according to WhoScored.
The 26-year-old scored 12 goals and provided six assists in 27 Premier League starts for Tottenham last season, according to WhoScored.
During the 2016-17 campaign, Son scored 14 goals and provided six assists in 23 league starts for the North London outfit, according to WhoScored.