King is thought to have picked up the injury to his left ankle during a collision with Everton striker Duncan Ferguson. He initially played on before limping off in the final minute.
King is not expected to play again this season and if he is ruled out of Sven Goran Eriksson's squad, to be named on 15 May, it is likely to ensure Sol Campbell's inclusion as one of England's four centre-halves alongside John Terry, Rio Ferdinand and Jamie Carragher and could lead to Manchester United's Wes Brown being called up as a fifth option.
King's absence will also hamper his club's Champions' League aspirations, and his injury took the gloss of an excellent victory over Everton. Spurs manager Martin Jol said that England fans should be proud of his resurgent team. This suggests he knows a lot more about young English players than English fans.
No doubt in the first category he has two of the best: the dazzlingly precocious Aaron Lennon and the slow-burning but increasingly impressive Michael Carrick. As far as the fans go, those at White Hart Lane, you can be certain, are identical to those up the road at Highbury. They want a winning team rather than the right set of passports or accents.
Maybe, though, there was just a touch of mischief from the worldly Dutchman on the way to next weekend's fourth-place showdown with Arsenal when he added that it was a "bit strange" to see an English team making it to the Champions' League semi-finals without a single home-grown player.
Spurs were rather more than a patriotic pleasure. They were a team confirming a remarkable season of progress: strong, fluent and with a creative touch that might have easily given them a winning margin of three or four goals.
Everton manager David Moyes said: "We had to thank Richard Wright for some excellent saves. Tottenham played very well; they may be the best team at Goodison this season."
Jol's domestically reared pièce de résistance, if the football nationalists will forgive the expression, was the 19-year-old Lennon. Quick, artful and brimming with self-assurance, he was a constantly darting rebuke to the woebegone decision of Shaun Wright-Phillips to leave his zone of comfort at Manchester City for a series of walk-on parts at Stamford Bridge.
While Wright-Phillips seems to shrink a little more with every public appearance, the similarly diminutive Lennon grows stronger.
Jol thinks it unlikely that Eriksson will promote Lennon above Wright-Phillips, citing the latter's much superior experience, but he made his point with a certain coyness. "It would be a great experience for Lennon, who is doing very well now," said Jol, "but that's Eriksson's business."
Goalkeeper Paul Robinson and playmaker Carrick are almost certainly on the World Cup plane and, against Everton, Jermain Defoe, Jermaine Jenas and Lennon all made strong claims to expand dramatically the Tottenham quota. In the process, Everton, denied again the vital creativity of Mikel Arteta, were able to produce no more than the battling spirit which has done so much to reclaim a season heading for disaster.
With understandable pride, Moyes is pointing out that Everton still have a good chance of achieving their second successive placing in the Premiership top 10 something of a quantum leap in the desperately under-financed effort to stabilise the club's place in the top flight.
However, the manager is quick to concede that without some major injection in the playmaking department, Everton's progress is likely to prove illusory. "That we are short in certain areas was well apparent today," he said. Most strikingly, it was in that part of the pitch left void-like, from Everton's perspective, by the absence of Arteta.
It was there where Tottenham's advance to the verge of Champions' League football could be most easily measured. Lennon was a wonderfully alert and tricky outlet, and just how valuable was only made clear when Jol, after some agonising, withdrew him in favour of the hulking defender Calum Davenport after 82 minutes. Jol was candid about his dilemma. "With [Duncan] Ferguson there and Everton obviously going to send in a lot of high balls, I wanted to strengthen our defence ... but I knew we could lose something further up front."
Indeed, after the solitary penalty-spot strike of Robbie Keane, Tottenham could well have lost everything. Wright had made a magnificent save from Jenas after he had been put through beautifully by Defoe, who later sent a brilliant shot against the crossbar, and Keane missed the kind of chance which, given his recent wolfish form, he should have taken. These chances could have made the last 10 minutes an opportunity for window dressing. Instead, Spurs hung on like tornado survivors.
If the conclusion was untidy to the point of confusion, it did little to take away the sense of a Spurs team who have indeed covered some vital terrain in the last few months.
They have become a team of both craft and purpose and in all the competitive imbalance of the Premiership this alone is cause for pleasure beyond White Hart Lane. If this success should extend to a significant contribution to World Cup success for the nation, it will be a matter of pride.
However, dressing Martin Jol up as St George might prove a little bit too much of a push. He works in football, not passport control. This means he takes his strength from wherever he finds it, which is why the Englishman Defoe was getting a rare chance to work with the Irishman Keane, not to boost the national game but because Mido, an Egyptian, had a groin injury.
Goal: Keane (33 pen) 0-1.
Everton: (4-4-2) Wright; Neville, Stubbs (Ferrari, 58), Yobo, Naysmith (Kilbane, 84); Davies (Ferguson, 66), Carsley, Cahill, Osman; Beattie, McFadden. Substitutes not used: Turner (gk), Weir.
Tottenham: (4-4-2) Robinson; Stalteri, King (Davids,9O) Gardner, Lee; Lennon (Davenport, 82), Carrick, Jenas, Tainio (Murphy, h-t); Defoe, Keane. Substitutes not used: Cerny, Barnard.
Referee: H Webb (South Yorkshire)
Booked: Everton Carsley, Neville; Tottenham Gardner.
Man of the match: Lennon.