Antonio Conte's uncertain future threatens to ruin Tottenham's spluttering season as the Italian returns to the bench for Wednesday's decisive Champions League showdown against AC Milan.

Conte is set to be back in charge of Tottenham after missing the last four games as he recovered from gallbladder surgery.

Watching on television back home in Italy while remaining in contact with his assistant Cristian Stellini, Conte saw Tottenham endure a choppy period that encapsulated the club's inconsistent form throughout his reign.

A pair of 2-0 wins against West Ham and Chelsea suggested Tottenham were on course to clinch a top four place in the Premier League with a flourish.

But that optimism was punctured by a dismal 1-0 loss at second tier Sheffield United in the FA Cup fifth round and another drab league defeat by the same score at Wolves on Saturday.

Conte has walked back into Tottenham's plush training complex this week to find a club not exactly in crisis -- they still sit fourth in the Premier League for now -- but once again drifting seemingly without direction towards an anti-climactic end to the season.

The north Londoners haven't won a major trophy since 2008 and even a manager of Conte's pedigree has been unable to break the drought.

While Jurgen Klopp memorably referred to his Liverpool players as "mentality monsters" during the peak of their success under the German, Tottenham's often limp response to pressure has made them look more like "mentality midgets".

Conte has portrayed Tottenham's problems as beyond his control, subtlely hinting at frustration with the transfer policy of chairman Daniel Levy without completely condemning him in public.

But the 53-year-old is taking his share of the blame from Tottenham fans, who have grown tired of his conservative tactics and questionable substitutions.

 'Massive boost'

Stellini's run of three successive wins prior to the FA Cup defeat made some Tottenham devotees wonder what the future would look like without Conte.

The former title winner at Chelsea, Inter Milan and Juventus has yet to sign an extension to a contract that expires at the end of this season and would surely be in demand from Serie A clubs if he was available.

Even if Tottenham finish in the top four to guarantee a return to the Champions League, it would be little surprise if Conte and Levy decided a parting of the ways was the only option in May.

Against that troubled backdrop, Tottenham host Milan in the last 16 second leg looking to overturn a 1-0 deficit from the first meeting at the San Siro.

Tottenham need Conte to lift their spirits ahead of a defining night in their season.

Crashing out against a mediocre Milan would be another sign of Tottenham's malaise, but victory could serve as the springboard for a more uplifting finale.

Tottenham defender Ben Davies acknowledged the significance of Conte being present for the Milan clash.

"It's been a while now but we have a huge game on Wednesday and it is very important he is with us," he said.

Conte has cut a disgruntled figure on the touchline this season, but Stellini echoed Davies's hope that Tottenham can be revived by their manager's return.

"Antonio will be a massive boost for us until the end of the season," Stellini said.

"It is important that Antonio is back. The team show to Antonio it is alive. They want to win, they want to dominate the game."