The South Korea star was one of the Premier League's standout players last season, sharing the Golden Boot with Mohamed Salah after scoring 23 goals.

But in the 2022-23 season Son has netted just four times in 21 league appearances, likely to fall short of 10 top-flight goals for the first time since his debut campaign in England (2015-16, four goals).

Son's per-90-minute averages of 0.2 goals, 0.26 expected goals, 1.0 open-play chances created and 0.36 goal involvements this season are all new lows for him in the Premier League.

Tottenham's lack of options in attack has perhaps contributed to Son keeping his place but, with the fit-again Richarlison pushing for a first start since before the World Cup after returning to action last month, the former Bayer Leverkusen man might find himself benched soon.

Certainly, Stellini – who is standing in for Antonio Conte again after the manager was ordered to return home to recover from surgery – does not appear to be offering Son any assurances over his place in the team.

"Every time when you pick the team you have to leave someone on the bench, and normally it is not important the player you have to maybe leave on the bench, it is about the team that has to play," Stellini told reporters before the derby visit of West Ham.

"It is important also that some important players stay on the bench for their effort when they come in. This is very important.

"We have experience with Sonny; we have experience with Richarlison; we have experienced with [Dejan] Kulusevski from the bench, they change the game.

"This is normal and it is normal for everyone, not because you have an important player he has to play compulsory.

"If he needs to play sometimes, also he needs to rest because we have a tough fixture [list]. We have a tough moment and we play many times.

"Sometimes you have to change the player and also to perform better."

Richarlison has made four substitute appearances since recovering from the hamstring injury he sustained in Qatar.

Stellini is "absolutely" convinced the Brazilian is now 100 per cent fit, hinting he sees him as a viable weapon as Spurs look to further their cause for a top-four spot.

Asked if he was looking for a way to fit Richarlison into the side, Stellini said: "Yes, this is our expectation for Richy.

"We were very unlucky with him because [of the injury] in the World Cup. We've missed Richy now for a long time. We missed Richy.

"In the best moment we had him at the start of the season, he was a player who changed our game.

"He changed the pace of the game during the game and when he started. He scored two goals in the Champions League and that was important.

"We've lost him sometimes and we have to accept it and work to have him back at the top, and his performance now I think could be good."