The injury, sustained during a pre-season friendly against Newcastle United in Seoul on August 3, has left the attacking midfielder and the club reeling.
The 1-1 draw was meant to be a celebration of Heung-min Son's final match for Spurs, but it turned into a nightmare for Maddison.
The 28-year-old was visibly emotional, leaving the pitch on a stretcher after a challenge that immediately raised concerns. Spurs head coach Thomas Frank called the incident "brutal" post-match, and scans later confirmed the worst: a torn ACL requiring surgery.
Tottenham issued an official statement, saying: "We can confirm that James Maddison will undergo surgery for a ruptured Anterior Cruciate Ligament (ACL) in his right knee. The surgery will take place in the coming days, and James will then begin his rehabilitation with our medical team.
"Everyone at Tottenham Hotspur wishes James a full and speedy recovery."
The injury is a cruel setback for Maddison, who has battled recurring fitness issues since joining Spurs from Leicester City two years ago.
With the 2026 World Cup looming, the timing could not be worse for the midfielder, who had been tipped to play a key role for both club and country.
Recent posts on X from Spurs fans reflect the gloom, with one user writing: "Gutted for Maddison. He's been so unlucky with injuries. Wishing him strength for the recovery." Another added: "This is a massive blow for Spurs. Maddison's creativity is irreplaceable."
Spurs have not yet commented on potential replacements or tactical adjustments, but Frank's squad now faces a significant challenge as they prepare for the new season without one of their key playmakers.
Maddison, known for his vision and flair, will begin a lengthy rehabilitation process, with the club pledging full support for his recovery.
Liverpool, with young Parma star Giovanni Leoni firmly in their sights, have three weeks to bolster their squad before the transfer window closes, aiming to address critical defensive vulnerabilities.
Liverpool are reshaping their squad with high-stakes transfers, as Darwin Nunez's blockbuster move to Al-Hilal nears completion and Harvey Elliott edges toward a switch to RB Leipzig.
Everton have opened talks with Manchester City to secure a season-long loan for Jack Grealish, but city are insisting any deal covers the midfielder's hefty wages in full.
Chelsea are intensifying their pursuit of RB Leipzig's Xavi Simons as they aim to bolster their attacking options for the upcoming Premier League and Champions League campaigns.
