The France international returned from a five-month lay-off following knee surgery only in December but has missed the team’s last two fixtures with a hip issue.
He has been unable to train since before Chelsea’s FA Cup win over Preston on January 6 and the manager said he is unsure when Nkunku, who was the Bundesliga’s top scorer last season with 16 goals for RB Leipzig before moving to west London for £52million, will be available again.
With fellow summer-signing Nicolas Jackson away representing Senegal at the Africa Cup of Nations for what is likely to be at least the rest of the month, and Armando Broja still looking to find form after being sidelined for nine months with an ACL injury, Pochettino has few options in Nkunku’s absence.
Chelsea’s goalscoring form has improved significantly on last season, when their return of 38 was the club’s lowest in the league for almost a century.
They currently have 34 at the halfway stage of the Premier League campaign, but despite this they have repeatedly found it difficult to break teams down, and have failed to convert high possession figures into clear chances.
They enjoyed 72% of the ball and had 18 shots on goal during Tuesday’s Carabao Cup semi-final first leg away to Middlesbrough, yet still slumped to a 1-0 defeat at the Riverside.
With the January transfer window still open for another fortnight, the Blues have the option of adding to their squad but Pochettino has acknowledged a swift decision needs to be made.
‘We need to be very clinical to take some decisions to think and see how we fix the problem,’ he said.
‘Nkunku out? I always say it’s an exciting project but situations like this make it more difficult to change the situation and grow at a different pace.’
The club have been linked with possible moves for Brentford’s Ivan Toney and Brighton’s Evan Ferguson in January to help bolster their attack.
‘(Nkunku) was the only player that was performing, of course in a different league, in Germany,’ said Pochettino. ‘But consistently scoring goals. That was the situation before the start of the season.
‘When (the injury) happened, we needed to see about Broja after one year (out injured), and Jackson moving from Villarreal, where he wasn’t top scorer.
‘The age of the players, (they are) young guys that need to adapt. That was why we felt a little bit more the hit of (losing) Nkunku.
‘He was consistently scoring goals. When you miss a player like this, you hope that players that maybe came here and need time to grow and score goals, it (became) a necessity, compulsory for Jackson to score in every single touch.
‘Or Broja, after one year out, needs now to play three games in a row. It’s difficult for him. It makes our job more difficult. It’s exciting this project, but situations like this make it more difficult. You have to grow at a different pace.’
For more stories like this, check our sport page.
Follow Metro Sport for the latest news on
Facebook, Twitter and Instagram.