In a clear indication of the malaise gripping Alli, the England international is far from certain to feature when Tottenham host Bayern Munich in a crucial Champions League clash on Tuesday.
That would have been unthinkable just two years ago when Alli was regarded as one of Europe's rising stars.
Since then, the 23-year-old has been stuck in a steady decline that raises questions about his long-term future in north London.
After appearing in four of Tottenham's five pre-season games, Alli was absent for the final friendly against Inter Milan due to the latest in a long line of hamstring issues.
Having missed games against Aston Villa, Manchester City and Newcastle, Alli was introduced on the hour for the 2-2 draw at Arsenal on September 1.
But that remains Alli's lone Premier League action this term, with his two other appearances coming in two of Tottenham's most underwhelming displays of the current campaign.
He was hauled off after 73 minutes of 2-2 Champions League draw at Olympiakos, with Tottenham reeling having blown a two-goal lead.
Alli's current lowly place in Pochettino's pecking order was clear for all to see when he was forced to start in under-strength Tottenham side for their League Cup third round tie at minnows Colchester last week.
That Alli delivered a limp performance in Tottenham's shock penalty shoot-out defeat suggested Pochettino had been correct to use his playmaker so little.
Alli's anonymous display in the depths of Essex was a fry cry from arguably the finest night of his career when his brace inspired Tottenham's 3-1 Champions League group stage victory over Real Madrid in November 2017.
Alli was hailed as Tottenham's next generational talent after a swaggering show capped by an impudent nutmeg of Real defender Sergio Ramos.
Yet since his star role in handing Madrid their first group stage loss for five years, Alli has been stuck in a rut.
Cutting an increasingly peripheral figure in Tottenham's midfield, Alli's form was a concern for Mauricio Pochettino for much of last season.
Although Alli's assist led to Tottenham's dramatic semi-final second leg winner for Lucas Moura at Ajax, that was a rare highlight.
Alli was a passenger when Tottenham's first Champions League final ended in an oddly lethargic 2-0 loss to Liverpool in Madrid.
He has fared no better for England, with Gareth Southgate leaving him out of the team for their recent Euro 2020 qualifiers due to his fitness problems.
Alli's woes are especially frustrating because evidence of his importance can be seen from UEFA's technical report into last season's Champions League.
He came fourth out of the players in the competition who made the most sprints per match on average with a total of 53.75.
Alli's runs into the area, often ending with a cool finish, have proved key over the years since his move from Milton Keynes Dons in 2015 -- but those moments have been few and far between of late.
While Alli has been struggling, Tottenham have found themselves in distress as well, rocked by the unsettling circumstances surrounding their failure to offload Christian Eriksen, Jan Vertonghen, Danny Rose and Victor Wanyama in the close-season.
All four expected to be sold and Pochettino admits it has been hard to keep his team focused.
Saturday's spirited 2-1 win over Southampton, achieved despite the dismissal of Serge Aurier, was a step in the right direction.
Speaking after scoring the goal that secured just Tottenham's third win in nine games, Harry Kane said: "Obviously we have had a couple of disappointing results recently.
"Going down to 10 men after 30 or 40 minutes, whatever it was, it was tough. Absolutely, it showed the character of the team.
"We're going through a tough spell, but we put everything out on the pitch. That is what a good win feels like."