Son was replaced at half-time by Steven Bergwijn as Tottenham drew 1-1 with the Magpies in their third league game of the season.
With the games coming thick and fast in different competitions at this embryonic stage of the season, the workload on players has started taking its toll.
Son has enjoyed an electrifying start to the season, scoring four times in a 5-2 win over Southampton last weekend before finding the back of the net again in the Europa League last Thursday but Tottenham will have to do without his services for the time being after he was consigned to the treatment table.
"It's an injury. We'll have him out for a while. It's his hamstring," Spurs manager Mourinho said after the game.
The 28-year-old is now set to miss Tuesday’s Carabao Cup fourth round tie against Chelsea as well as the Europa League final qualifying game against Maccabi Haifa two days later and the trip to Manchester United in the Premier League this weekend.
Mourinho has already started complaining about the fixture pile-up.
The former Chelsea and Manchester United manager added: “This is just the first one. Tuesday another one, Thursday another one and Sunday a couple more. This is the respect Tottenham gets.”
